'nonisogonal' originates from English, specifically formed by prefixing 'non-' to 'isogonal', where 'non-' meant 'not' and 'isogonal' comes from Greek roots 'isos' meaning 'equal' and 'gonia' meaning 'angle'.

'isogonal' entered mathematical English via New Latin and subsequent use in mathematical French and English from Greek elements 'isos' and 'gonia'; 'nonisogonal' is a modern English formation created by adding the negative prefix 'non-' to that established term.

Initially, the component 'isogonal' meant 'equal-angled' in a geometric sense, and by prefixing 'non-' the modern term came to mean simply 'not equal-angled' or 'not isogonal'.