'subcontract' originates from Latin elements: the prefix 'sub-' (meaning 'under' or 'below') combined with 'contract', ultimately from Latin 'contrahere'/'contractus'.

'contract' came into English from Latin 'contractus' (from 'contrahere') via Old French and Middle English; 'sub-' is a Latin prefix. The compound 'subcontract' was formed in modern English by attaching 'sub-' to 'contract' to denote assigning part of a contract to another party.

Initially, 'contract' in Latin meant 'to draw together' and later 'a binding agreement'; 'subcontract' came to mean 'to assign part of a contract to another (party)', which is the current meaning.