Professor Máirtín Ó Murchú gives the origin of ‘bainistí’ as a compound of ‘banas’ and ‘tighe’ – Jim O’Donnell points out that ‘economy’ derives from Greek ‘oikos’, ‘house’. ‘Banas’, based on ‘ben’, is translated in DIL as ‘the condition of a woman; womanliness; woman’s activities’...

The compound ‘banas’ and ‘tighe’ originally had the sense of ‘that which relates to the woman of the house’, this developing to ‘the management of the house’ and later to ‘management’, according to Máirtín Ó Murchú...

Finally, note that, while both ‘bainistí’ and ‘bainis’ are based on ‘ben’ (‘woman’), ‘bainistí’ is not directly related to ‘bainis’ (‘wedding’), the earlier form of which, ‘banais’ (translated as ‘marriage-feast, wedding’ and ‘feast, banquet in general ’ in DIL), is a compound of ‘ben’ and ‘feis’ (originally ‘spending the night, sleeping with’, hence ‘spousal’, according to DIL).