'non-phototactic' originates from the Latin prefix 'non' meaning 'not' and from modern scientific formation using Greek roots 'photo-' from Greek 'phōs' meaning 'light' and 'taxis' meaning 'arrangement' or 'movement'.

'phototaxis' is a scientific coinage based on Greek roots ('phōs' + 'taxis') in modern biology; 'phototactic' was formed by adding the adjectival suffix '-ic', and the negative prefix 'non-' was later attached in English to form 'non-phototactic'.

Initially the component 'phototaxis' referred specifically to movement toward or away from light; 'non-phototactic' has retained the literal negated meaning 'not exhibiting phototaxis' without major semantic shift.