'uni-' originates from Latin, specifically the word 'unus', where the prefix 'uni-' meant 'one', and 'nerved' comes from Latin 'nervus' meaning 'sinew' or 'nerve'.

'uni-nerved' formed in Modern English by combining the Latin-derived prefix 'uni-' (from 'unus') with the adjective 'nerved' (from Old French 'nerf', ultimately from Latin 'nervus'), producing a compound meaning 'having one nerve/vein'.

Initially it described literally 'having one nerve or sinew'; in botanical usage the meaning narrowed to 'having a single principal vein' and has remained a technical descriptive term.