'shoreline-related' originates from Modern English, specifically formed from the compound 'shoreline' + 'related', where 'shoreline' meant 'the line along the shore' and 'related' meant 'connected to or pertaining to'.

'shoreline' developed from the combination of 'shore' + 'line'; 'shore' traces back to Old English roots meaning 'coast' and 'line' ultimately from Latin 'linea' (via Old French/Old English developments). 'Related' comes from Latin 'relatus', the past participle of 'referre', passing into Old French and then Middle English as 'relaten/related'. Together, the modern compound arose in recent Modern English usage to describe things connected with the shoreline.

Initially, the components referred simply to 'shore' (coast) and 'line' (a boundary) and to being 'related' or 'connected'; over time they combined to form a compound adjective meaning 'connected with or characteristic of the shoreline'.