alligator

Alligator comes from early Modern English forms like alligater and aligarto, which came from Spanish el lagarto, meaning 'the lizard,' itself from Latin lacertus ('lizard').

The Spanish article 'el' fused right onto the noun as English speakers borrowed the phrase, turning 'the lizard' into a single word. Over time its spelling settled into 'alligator,' possibly nudged by the unrelated Latin word alligator, meaning 'one who binds.'

The facts don't support a confirmed English cognate, though the coincidental resemblance to Latin alligator ('one who binds') may have shaped its final spelling.