'Coast-related' originates from Modern English as a compound of 'coast' and 'related'. 'Coast' ultimately comes from Latin 'costa' (via Old French 'coste'), where 'costa' meant 'rib' or 'side' and developed the sense 'shore'; 'related' comes from Latin 'relatus' (past participle of 'referre' via Old French/Latin), where roots conveyed the sense 'carried back' and later 'connected'.

'Coast' changed from Latin 'costa' to Old French 'coste' and entered Middle English as 'coste' before becoming modern English 'coast'. 'Related' developed from Latin 'relatus' through Old French and Middle English forms of 'relate' and became the adjective 'related' in Modern English. The compound 'coast-related' is a modern English formation combining these elements.

Initially, 'coast' meant 'rib' or 'side' and later shifted to mean the shoreline; 'related' originally carried senses tied to 'bringing back' or 'reporting' and evolved to mean 'connected'. Together the compound now means 'pertaining to the coast'.