'wavelength-selective' is a modern English compound formed from 'wavelength' + 'selective'. 'wavelength' itself is an English compound of 'wave' and 'length'. 'selective' derives from Latin 'selectus' (past participle of 'seligere'), where the prefix 'se-' meant 'apart' and 'legere' meant 'to choose'.

'wavelength' was coined in scientific English in the 19th century by combining 'wave' (Old English roots, later Middle English 'wave' meaning a moving ridge or disturbance) and 'length' (from Old English 'lengðu'). 'selective' entered English via Latin 'selectus' and Old French forms and was combined with the suffix '-ive' in Modern English; the compound 'wavelength-selective' emerged in technical usage in the 20th century within optics and radio engineering.

Originally the component words referred to concrete concepts ('wave' as a moving disturbance; 'length' as extent; 'select' as to choose). Over time, in technical contexts they combined to form a term meaning 'choosing or responding based on wavelength', a specialized sense used in physics and engineering.