a, b, d, r, u are letters that make 'rub-a-dub'
dub, rub, Ru are words within 'rub-a-dub'
1 possible definitions for 'rub-a-dub'
Under this definition, rub-a-dub is a noun and has the following properties:
rataplan, drumbeat have the same meaning as 'rub-a-dub'
'rub-a-dub' can be a type of sound.