Copulative a

The copulative a (also a copulativum, a athroistikon) is the prefix a- expressing unity in Ancient Greek, e.g. in a-delphos "brother", from *sm̥-g^u̯elbhos literally "from the same womb" (c.f. Delphi). it goes back to a PIE *sm̥-, cognate to English same (see also Symbel). The disappearance of the s- is a specifically Greek sound law, and the cognate forms in other languages typically still preserve it, e.g. Sanskrit saṃ-, present e.g. in the term for the language itself, viz. saṃ-s-kṛtā "put together".

See also: privative a.