'arctoidean' ultimately originates from New Latin 'Arctoidea', which itself comes from Greek 'arktos' meaning 'bear' combined with the taxonomic suffix '-oidea' (indicating a superfamily).

'arctoidean' was formed in modern scientific English from the New Latin taxon 'Arctoidea' (used to name the superfamily); the adjective/noun sense developed by adding the English adjectival/denominal ending '-ean' to that taxon name.

Initially the root referred specifically to 'bear' ('arktos'), but in scientific usage it came to denote a broader group of 'bear-like' carnivorans (the superfamily Arctoidea); 'arctoidean' now refers to members of or traits related to that clade.