'unimorphic' originates from the Latin prefix 'uni-' (from Latin 'unus', meaning 'one') combined with the Greek-derived element '-morphic' (from Greek 'morphē', meaning 'form').

'unimorphic' was formed in modern scientific English by combining 'uni-' + '-morphic', influenced by earlier formations such as 'monomorphic' (from Greek 'monos' 'single' + 'morphē').

Initially and historically it has meant 'having one form'; this core meaning has been largely stable into contemporary usage.