'allogamize' originates from Greek, specifically the word 'allogamia', where 'allos' meant 'other' and 'gamos' meant 'marriage'; the verb-forming suffix '-ize' comes ultimately from Greek '-izein' via Latin and French.

'allogamize' developed from New Latin 'allogamia' and the English noun 'allogamy'; in modern English the noun 'allogamy' took the verb-forming suffix '-ize' to produce 'allogamize'.

Initially it referred to the concept 'other-marriage' or cross-fertilization as a noun; over time it acquired the verbal sense 'to cause cross-fertilization' or 'to make something allogamous'.