[Image] SKANDHA in the Sanskrit Dictionary (Comparing MW and Apte) primarily means 'bough, branch; shoulder bone (scapular); break, fracture.'  It also means 'a branch of knowledge', 'a chapter in a book', and 'a division of an army' which are obvious metaphorical extensions. Added to this the word apparently means 'a troop or multitude', which is not obvious from the etymology. The supposed root is skandh 'to collect'; sometimes confused with skand 'spring, jump, spurt'  from PIE *skand (AHD) or related to Latin scandare 'to climb, ascend, descend'. Frankly it would seem that the dictionary definition and etymology are inconsistent, except, funnily enough in the Buddhist sense of a 'collection'. However in point of fact the skandhas are not collections at all, and I can't help but wonder if 'collections' have been tacked on here precisely to accommodate Buddhist usage, thus fouling the trail.
Clearly the main meaning of 'branch' (or a tree or a line) is not related semantically to 'collect', but etymologists also draw attention to semantic similarities with Greek κλάδος (klados) 'branch, shoot, an offshoot' (CSED); from PIE *kldo- from *kel 'to cut' and giving rise to English 'calamity, clade, clast, gladiator' etc. The problem here is that, while the semantic field is very similar, the phonetics don't seem to be related.

Another possibility is that skandha comes from a PIE root *(s)k(h)ed or *sked (AHD). It has a form  nasalised form *skend and partly covers the semantic field 'to split' - which would connect it semantically with *kel 'to cut' This root is not well represented in Sanskrit, but is the root behind English words such as 'scatter, shatter and shingle'. If this is the PIE root then it is not well represented in Sanskrit either. I think we have skandha < *skand 'to split off, to branch' and that skandhayati is a denominative. I don't see any other related forms. This rarity of form may have led to confusion with Sanskrit skandh and (homonymous) skand 'to jump'. However I can't be sure of this without a lot more research.
Thus the etymology of the word is obscure. However I think we can agree that 'aggregate' as a translation is madness, and that other modern translations of Buddhist usage (group, mass, heap) are almost equally unhelpful. If indeed skandha were related to Greek klados, at least semantically, then we might translate skandha as 'branch'. The skandhas, then, might be thought of as the five 'branches of experience'. This might be interesting in light of the word prapañca (On the origin of the word prapañca from the branching of the hand into five fingers see: Translating Prapañca). We might postulate that prapañca (becoming fivefold) is related to the five branches of experience, though clearly some work would be required to establish this speculation. Since this is a blog rather than an academic publication I can take liberties and so for this essay I translate skandha as 'branch'; as one of five branches (pañcaskandha) of experience; it's justified by the dictionary and, as we will see, it works pretty well here. I would note that the branching of the end of limbs into five digits is universal amongst animals. What appear to be exceptions (horse hooves etc) turn out to have have fused two or more of the five digits and embryonic forms often begin with five distinct digits. This ought to be a very common basis for metaphors and we should not be surprised to find it.

Richard Gombrich (What the Buddha Thought, 2009) has suggested with reference to the term pañc'upādāna-kkhandhā, that Pāli upādāna-kkhandha should be read as a contraction of upādāna-aggi-kkhandha where aggi-kkhandha means 'a blazing mass' but c.f. Sanskrit skandhāgni 'fire made with thick logs'. (MW) I now wonder whether aggi-kkhandha just means 'a burning bough'. The phrase pañca upādānakkhandha is often rendered 'five aggregates of clinging', where we might read it as 'five branches which are fuel [for the fire]'; where upādāna means 'fuel' and 'the fire' is 'the fire of being'. I find the connection with the extended fire metaphor entirely plausible (see Playing with Fire; and Everything is on Fire!) and I suggest that it works even better when khandha is understood as 'branch'.
Having looked, somewhat inconclusively, at the meaning of skandha, let us now examine a passage from the Pāli Mahāpuṇṇama Sutta (M 109; iii.15ff ) which tells us something about the relationships of the skandhas: The four elements are the reason for, the condition for the manifestation of the branch of form.  Contact is the reason for, the condition for the manifestation of the branch of sensations. Contact is the reason for, the condition for the manifestation of the branch of recognition. Contact is the reason for, the condition for the manifestation of the branch of volitions.  Name & form is the reason for, the condition for the manifestation of the branch of cognition. Here someone has tried to show the dynamics of the skandhas. The form branch (rūpa-kkhandha) of experience is made up from the four elements: earth, water, fire and wind (catur mahādhātu: paṭhavī, āpo, tejo, vāyo;); or in experiential terms: resistance, cohesion, heat and movement. There's every reason to believe that just as cakkhu 'the eye' stands for the visual faculty; that paṭhavī stands for the experience  of resistance. Before looking at the other branches let us look at an interesting passage (SN 35.93) which sheds further light on this.  The production of cognition is conditioned by a pair. Visual-cognition arises conditioned by the eye and forms. The eye is impermanent, reversible, and unstable. Forms are impermanent, reversible, and unstable. So this pair is transient, wavering, impermanent, reversible, and unstable.
Visual-cognition is impermanent, reversible, and unstable. Whatever the reason (hetu) or condition (paccaya) for the arising of visual-cognition, it is impermanent, reversible, and unstable. So how could visual-cognition ever be permanent?
These three things [i.e. forms, eye, & visual-cognition] coming together, encountered and co-occurring are called visual-contact (cakkhu-samphassa). Visual contact is impermanent, reversible, and unstable. Whatever the reason or condition for the arising of visual-contact, it is impermanent, reversible, and unstable. So how could visual-contact ever be permanent?
The contacted (phuṭṭha) is sensed (vedeti); the contacted is willed (ceteti); the contacted is recognised (sañjānāti). So these things (dhammā) are transient, wavering, impermanent, reversible, and unstable. [The other senses are outlined in identical terms.] So now our model has rūpa being made up of the elements (dhātus); and contact (phassa) is the condition for the next three branches. S 35.93 fills in a gap here. Contact comes about when rūpa, cakkhu (the eye, or visual faculty) and cakkhuviññāna 'visual cognition' come together; the latter in fact being conditioned by the former pair. And then contact is sensed, willed, and recognised. 
The last three mental actions are equivalent to the three middle branches. We can match up the verbal and nominal forms: vedanā vedeti 'he senses sensations'; saṅkhārā ceteti 'he wills volitions'; and saññā sañjānāti 'he recognises names' or 'he recognises recognitions'. However note that the three verbal forms are in a different order than the nominal forms. And this is unusual. Sue Hamilton's comprehensive survey of the skandhas in Pāli finds that they always occur in the same order (Early Buddhism, p.72). 
Next we add the three branches of vedanā, saññā and saṅkhārā to rūpa to make up nāmarūpa; and nāmarūpa is the condition for the arising of viññāna.
The astute reader will have already spotted a problem here: viññāna (associated with the six kinds of senses) is the condition for the arising of vedanā, saññā and saṅkhārā and thus indirectly the condition for  nāmarūpa. Thus we have two models in which the direction of the relationship between nāmarūpa and viññāna goes in opposite directions. How can we have two mutually exclusive models which are both  canonical? In the  Mahānidāna Sutta (D 15) nāmarūpa and viññāna condition each other? If this was the original idea it might have survived in two fragmentary and contradictory forms with unidirectional conditionality. Or perhaps the Mahānidāna Sutta sought to harmonise the two different models by combining them. Certainly the Mahānidāna Sutta says that nāmarūpa is root, cause, origin and condition for contact (tasmāt iha ānanda, eseva hetu etaṃ nidānaṃ esa samudayo esa paccayo phassassa, yadidaṃ nāmarūpaṃ). Nāmarūpa is quite a problematic term in its own right: see Nāmarūpa. And in another model we find "nāma is 'sensation, recognition, impulse, contact and attention'." (vedanā, saññā, cetanā, phasso, manasikāro – idaṃ vuccati nāmaṃ. S ii.3). And this in a model where phassa is a stage in its own right that comes after nāmarūpa. 
It must be the case that viññāna is being used in at least two different senses: cakkhuviññāna (and the other sense-viññānas) and viññāna (as a standalone) cannot be referring to the same process or even the same kind of process. The standard explanation is that viññāna 'furnishes bare cognition of the object' (Nyanatiloka. Buddhist Dictionary) but this is still contradictory. In the model of the five branches we're looking at viññāna simply cannot amount to 'bare cognition' since it is preceded by vedanā, saññā and saṅkhārā. Without 'bare cognition of the object' how could these three exist? Is the problem with the phrase 'bare cognition'? 
Elsewhere I have pointed out that viññāna is said in Pāli to be always related to the sensory stimulus that conditioned it. For example in the Mahātaṇhāsaṅkhaya Sutta. (MN 38. PTS M i.259): Bhikkhus from whatever condition viññāṇa arises, it is called that kind of viññāṇa. Viññāṇa arising with the eye and form as condition, is called eye-viññāna (i.e. visual cognition). From the same sutta we know what viññāna is not: "that which speaks and feels, that which experiences the good and bad." (yvāyaṃ, bhante, vado vedeyyo tatra tatra kalyāṇapāpakānaṃ kammānaṃ vipākaṃ paṭisaṃvedetī ti) This is cited as an example of a wrong view. We also know that Buddhists do not posit a 'theatre of consciousness', a metaphorical container in which experiences happen, since viññāna is seldom if ever used in the locative case, and where it is the text is usually arguing against a wrong view.

Idiosyncratic, but none the less insightful, bhikkhu Ñānavīra, says
Consciousness (viññāṇa) can be thought of as the presence of a phenomenon, which consists of nāma and rūpa. Nāmarūpa and viññāṇa together constitute the phenomenon 'in person'--i.e. an experience. The phenomenon is the support (ārammaṇa) of consciousness, and all consciousness is consciousness of something (viz, of a phenomenon). [Notes on Dhamma, p.81] I don't think Ñāṇvīra has solved the problem I have identified here, i.e. the role of viññāṇa in the khandhas.  Since nāma depends on sense-viññāṇa. However he does add an interesting caveat to this discussion.
Consciousness, it must be noted, is emphatically no more 'subjective' than are the other four upādānakkhandha (i.e. than nāmarūpa)... It is quite wrong to regard viññāṇa as the subject to whom the phenomenon (nāmarūpa), now regarded as object, is present. [Notes on Dhamma, p.82] Back in April 2012 I argued that Westerner terms like subjective and objective only obscure the discussion. In the Buddhist model of consciousness, subject and object are not relevant. This is a corollary of the idea that existence and non-existence don't apply to experience. We only get confused trying to marry the two modes of thinking about our experience of being aware. Indeed to think of viññāṇa as 'consciousness' is demonstrably wrong (see  The 'Mind as Container' Metaphor.) Nāṇavīra himself implies this, but doesn't not make the leap to rejecting the translation outright. We have our discussions as if Western concepts like consciousness, subject, object, etc., are givens. But they are not. The early Buddhists don't seem to have thought in these terms. Where they encounter this style of thinking, they tend to treat it as irrelevant to the task at hand. Ontological questions that fascinate Westerners, are just a distraction to early Buddhists. We are not trying to understand our self or our consciousness in the abstract, we are trying to understand why we suffer. Of course early Buddhists had a raft of assumptions about their experience of the world and we need to tease these assumptions out in order to understand their worldview. But imposing modern philosophical jargon often obscures more than it reveals.

This essay has at least shown how translating skandha as 'branch' and pañcaskandha as 'the five branches [of experience]' might work, and might be more comprehensible than present alternatives. It is intrinsically interesting that at least one of the strands that made up the Pāli Canon attempted to give the five branches of experience a temporal sequence, though whether it works is moot. My previous understanding, based on reading Sue Hamilton was that the skandhas did not form a sequence, but were to be taken collectively as the "apparatus of experience". That this attempt breaks down with the inclusion of viññāṇa is a puzzle that I'm sure I will come back to.

We have considerable work to do still to untangle early Buddhist ideas about why we suffer from Western ideas about our existence and the ontology of the self with which they seem to have been snarled. The first step in any comparative philosophy will be to understand early Buddhism on it's own terms and I don't think we have done this yet.
~~oOo~~

Note 5/5/13

In article by Collete Cox I found this the re the *Mahāvibhāṣā "In a discussion of the implications of the various meanings of the term "aggregate," or skandha, as a heap (rāśi), a bundle, an assemblage, or as a collection..." Thus the usage 'heap' predates Conze!
Cox, Collett. (2004) 'From Category To Ontology: The Changing Role of Dharma in Sarvāstivāda Abhidharma.' Journal of Indian Philosophy. 32: 543-597.