conc▪ In itself a borrowing from Syr with the original meaning of ‘piece of land retained and enclosed by its proprietor for sowing and planting trees’, the word probably belongs, ultimately, to the same (W?)Sem root *ḤKR ‘to set apart and retain (obstinately) for o.s.’ from which also other Ar items are derived (these however without Syr mediation). Most prominent among the latter in MSA is probably ĭḥtakara ‘to monopolize, hold a monopoly’, from †ḥakira ‘to be obstinate, keep s.th. for o.s., not allowing anyone a share in it’ (cf. also †ḥakara ‘to act wrongfully’), see ↗ḥakar, ↗ḥikr, and ↗ḤKR.
▪ In contrast, Dolgopolsky2012 thinks that the source of Ar ḥākūraẗ, Syr *ḥakūrā ‘field’, goes back to a CSem *ḤKR ‘field in cultivation’. The author puts this together with Sum agar (< Sem) ‘territoire irrigué’ and forms in IE langs (< IE *ag̑ro-s ‘field, field in cultivation’) like oInd aǧra-ḥ ‘field, plain’, Grk agrós ‘field, farm’, Lat ager, Ge Acker, Engl acre ‘field’. According to Dolgopolsky, the Sem, IE (and Alt) forms go back to Nostr *XakER˅ ‘plain’ (in descendant langs: ‘field’)