'Metazoa' originates from New Latin, ultimately from Greek 'metazōa', where 'meta-' meant 'after, beyond' and 'zōon' (plural 'zōa') meant 'animal'.

'Metazoa' was formed in New Latin from Greek roots (meta- + zōon) and entered scientific English usage in the 19th century as a taxonomic name for multicellular animals.

Initially used to distinguish animals that are not single-celled protozoans, it evolved into the modern taxonomic sense referring broadly to multicellular animals (Animalia).