Copulative a
The copulative a (also a copulativum, a athroistikon) is the prefix ἁ- (ha-) or α- (a-) used to express unity in Ancient Greek, derived from Proto-Indo-European *sm̥-, cognate to English same (see also symbel). An example is ἀδελφός (adelphós 'brother'), from *sm̥-gʷelbhos, literally meaning 'from the same womb' (compare Delphi).