'long-finned' originates from the combination of 'long' and 'fin,' where 'long' meant 'having great length' and 'fin' referred to the appendage on a fish or marine animal.

'long-finned' evolved from the Old English word 'lang' for 'long' and the Old Norse word 'finnr' for 'fin,' eventually becoming the modern English word 'long-finned.'

Initially, it meant 'having long appendages on a fish,' and this meaning has largely remained the same in modern usage.