In my understanding:
Yes there are varying meanings depending on context. It may also have following three meanings: fabricators or fabricating processes or fabricated things. In the most general way perhaps sankhara can be understood as "thing upon which something else depends" (Ven. Nanavira). But, in the dependent origination the Buddha must have used the word with a specific meaning (bodily, verbal, and mental sankhara).
For myself I usually translate it as 'activities' (mainly in context of the 5 aggregates). Later on I came across some translators using this terminology also and I think it is a useful one. In other words, it is something that is active, that moves, creates, wills, that does. Sankhara here being a collection of all sorts of things, but sharing the 'activity' aspect which we don't find in the other aggregates. For example, consciousness in itself is not 'active', it is not moving.
Thanks, reflection. But don't all sankhara (including five aggregates) directly or indirectly arise due to ignorance?
In a sense, yes, but it is indirectly. All aggregates are here because of ignorance in past lives. If there was no ignorance in past lives, we would be nibbana-ed and there would be no more aggregates. However, in dependent origination the link is directly
from ignorance to sankhara. But ignorance does not lead directly to the birth/arising of aggregates. The important link between those is the acting on ignorance. If there theoretically would be only ignorance but no acts, no intentions, there is no kamma.
Only if ignorance actually is acted upon (which it naturally will be), it gives rise to kamma fabrications, it gives rise to the birth, the rearising of the aggregates. This acting upon ignorance (aka kamma) is how I see sankhara in context of dependent origination. And since intention/kamma is of central importance in the entire Dhamma, it's quite logical the Buddha wouldn't leave it out of dependent origination. Now I didn't know what would define a 'usual interpretation', but it seems to me the quote by Bhikkhu Bodhi says this 'usual interpretation' is saying the same as I'm saying. So perhaps you can find more there.
Also, if the sankhara in the dependent origination are to be understood as "Kamma" then the question is: how do these kamma sankhara give rise to such consciousness leading to birth? Does this question fall under Acinteyya?
Kamma, or intentions. How it roughly happens is at death there is no letting go because one still is attached to the six senses, there is still a sankhara based on sustenance/clinging (upadana). This sankhara, which is also based on other sankharas, initiates the new birth. Here you can combine the two life-to-life transitions of dependent origination into one to get the full picture. They basically describe the same process. Trying to understand this is not accinteyya, that would be for example to try and figure out exactly what kamma leads to what rebirth.
Yes, I also like to understand it as a process, but I am not clear how this process works.
So for clarity, now we're back to sankhara as one of the five aggregates, not sankhara in dependent origination. As I said, I think the most important sankhara in this process is the intention that turns towards a particular consciousness. In other words, the mind going out to for example, sounds. In meditation you can get a sense of this when sounds begin to intrude into awareness again after they were not noticed for a while. You see the mind is going after it; this is a sankhara. There is quite a famous story of Ajahn Chah being able to consciously decide whether he would hear sounds or not. With the body consciousness it can also be quite obvious; when pain arises, the mind often moves towards the pain. This is an activity, this is a sankhara. And it is an important one because it can be (but is not necessarily) based on attachment to the senses.
There are other sankhara in the process but these I personally think are of minor importance. For example, the feelings or images arising in the mind are created, are sankhara-ed. Same with other senses.
But we can try to get our head around it, but as I said, seeing things in meditation is more clear. The Buddha's words are like describing the taste of a banana; you can't recreate the taste by thinking about the description of it. At times contemplating these deep teachings may be useful, but I think it is at least just as fruitful to put these things aside and simply still the mind. And then to simply ask ourselves, what am I attached to? And if I die, how would I act upon that attachment?
Hope it creates some clarity. If not, don't break your brain over it.
Samadhi is important in understanding sankhara:
"The individual who has attained internal tranquillity of awareness
, but not insight into phenomena through heightened discernment, should approach an individual who has attained insight into phenomena through heightened discernment and ask him: 'How should fabrications be regarded?
How should they be investigated? How should they be seen with insight?' The other will answer in line with what he has seen & experienced: 'Fabrications should be regarded in this way. Fabrications should be investigated in this way. Fabrications should be seen in this way with insight.' Then eventually he [the first] will become one who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment.http://www.accesstoinsight.org/tipitaka ... .than.html