'sex-linked' originates from Modern English, specifically the compound of 'sex' and 'linked', where 'sex' meant 'biological category (male or female)' and 'link' meant 'to tie or connect'.

'sex' comes into English via Old French 'sexe' from Latin 'sexus', and 'link' comes from Middle English 'link' (from Old English and Old Norse sources); these elements combined in Modern English to form the compound 'sex-linked'.

Initially the separate parts meant 'gender' and 'to connect'; over time the compound came to mean 'connected with sex', particularly in genetics where it describes traits associated with sex chromosomes.