'humectant' originates from Latin, specifically the verb 'humectare', where 'humect-' meant 'to moisten' and the English/Latin-derived suffix '-ant' formed nouns/adjectives meaning 'performing or causing'.

'humectant' was formed from the Latin present-participle root 'humectans' (meaning 'moistening') and was adopted into English as a technical term (late 19th–early 20th century) to describe substances that retain moisture.

Initially it referred broadly to 'moistening' or 'that which moistens'; over time it came to specifically mean 'a substance or agent used to retain moisture' in contexts such as cosmetics, food, and materials.