towel
Pronunciation: /ˈtaʊəl/
noun
verb ( towels, towelling, towelled; US towels, toweling, toweled)

Origin:
Middle English: from Old French toaille, of Germanic origin. Sense 2 of the verb dates from the early 18th century; sense 1 from the mid 19th century

Spelling rule
Double the l when adding endings which begin with a vowel to words which end in a vowel plus l (as in travel):