'monoeciousness' originates from New Latin (formed from 'monoecius'), ultimately derived from Greek, specifically the word 'monoikos', where 'mono-' meant 'one' and 'oikos' meant 'house'.

'monoeciousness' developed from the adjective 'monoecious' (New Latin 'monoecius'), which in turn comes from Greek 'monoikos' ('mono-' + 'oikos'). The scientific adjective entered English via Medieval/Scientific Latin and later formed the noun with the suffix '-ness'.

Initially related to the idea of 'one house' (literally 'living in one house'), it came to be used in botany to mean 'having male and female reproductive organs on the same individual', and now denotes the state or condition of that trait.