'nonspectral' originates from Modern English, specifically the prefix 'non-' + the adjective 'spectral', where the prefix 'non-' meant 'not' and 'spectral' derives from Latin 'spectrum' (from 'specere') meaning 'appearance' or 'to look'.

'spectral' changed from Latin 'spectrum' into Late Latin/French forms such as 'spectre'/'spectralis' and then into Middle English as 'spectral'; the compound 'nonspectral' was formed in Modern English by adding the negative prefix 'non-'.

Initially related to 'appearance' or 'image' (Latin 'spectrum'), it came to mean 'relating to a spectrum' in scientific contexts; 'nonspectral' developed to mean 'not relating to or not exhibiting a spectrum'.