'Aequorin' originates from the Latin word 'Aequorea,' referring to the jellyfish species Aequorea victoria, from which the protein was first isolated.

The term 'aequorin' was coined in the 1960s following the discovery of the protein in the jellyfish Aequorea victoria.

Initially, it referred specifically to the protein isolated from jellyfish, and this meaning has remained consistent in scientific contexts.