'alkylidene' originates from 'alkyl' and the suffix '-idene', where 'alkyl' refers to a type of hydrocarbon group and '-idene' indicates a double bond.

'alkylidene' was formed by combining 'alkyl' with the suffix '-idene' to denote a specific type of chemical radical.

Initially, it referred to a specific type of chemical radical, and this meaning has largely remained the same in modern usage.