I too find
concentration to be a poor translation for
samadhi. My meditation teacher, Sayadaw U Tejaniya, prefers
stability or
stability of mind. In terms of meaning, I think it’s really good as it makes sense in terms of practice—much better than
concentration. However, I wasn’t satisfied. I set out to find the best translation, and here’s the result:
Samādhi is the noun for the verb
samādhiyati.
Samādhiyati is the passive form for the active verb
samādahati.
Samādahati:
sam “together” +
ādahati “put, place”. So, it means “put together” or “place together”. The English word
compose shares a strikingly similar origin:
com “together” +
ponere “put, place”. (Source:
http://www.myetymology.com/english/composure.html and
http://dictionary.reference.com/etymology/compose) In modern usage, both words can also mean “to still or calm down the mind”.
Composed also share strikingly similar meaning as
samāhita (participle of
samādahati), which means “settled, composed, collected”. Both denotes a mental state that is not scattered, not “all over the place” (so to speak), but gathered, collected, composed.
Extrapolating from that, the noun
samādhi should rightly mean “composure, collectedness”.It is probably the best English equivalent of
samādhi.
I’m in the midst of writing an article (which is becoming a booklet) on this among other things related to samādhi. I’m pleasantly surprise to find this discussion on the very topic that set me off on a research spree! Shall share the work with you all when I’m done with it.