'crawler' originates from the English word 'crawl', which comes from the Old Norse word 'krafla', meaning 'to claw or scratch'.

'krafla' transformed into the Middle English word 'craule', and eventually became the modern English word 'crawl', from which 'crawler' is derived.

Initially, it meant 'to move slowly or with difficulty', and this meaning has largely remained the same in modern usage.