'halation' originates from the English base 'halo' combined with the suffix '-ation' (from Latin '-ationem'), where 'halo' ultimately comes from Greek 'halōs' meaning 'threshing floor' or 'disk' and was used for a ring or circle of light.

'halation' was formed in English by attaching the productive noun-forming suffix '-ation' to 'halo' (which entered English via Latin/Greek). The element 'halo' derives from Greek 'halōs' and passed into English usage as 'halo' before the compound noun 'halation' developed, especially with the rise of photographic and optical terminology in the late 19th to early 20th century.

Initially it meant 'the condition or quality of forming a halo (a ring of light)'; over time the term became specialized in photographic and imaging contexts to describe the specific optical effect of light spreading or veiling glare around bright areas.