assimilated form in Latin of the prefix in- prefix² before initial l, which is written in the same way in English, as in il-lation, il-luminate. Usually only one l is heard; but both (or a prolonged l) may be pronounced when distinctive emphasis is laid on the prefix, as in il-lision, il-lude, distinguished from e-lision, e-lide. For the varieties of meaning, ‘in, on, into, upon’, see in- prefix².

assimilated form in Latin of the negative prefix in- prefix³ before initial l, which remains in the same form in English, as in il-legal, il-legitimate, il-literate. Also used in forming negatives in English on the analogy of Latin, as in illogical adj., illoyal adj., and in such nonce-words as il-level, il-locomotive, etc. When the main stress immediately follows, an effort is often made to give the separate effect of the prefix by pronouncing both l's, or combining them in one prolonged l; this is especially the case when rhetorical stress is laid on the prefix, as in ‘You call this a Liberal measure; I consider it thoroughly il-liberal’.