UK:*UK and possibly other pronunciationsUK and possibly other pronunciations/ˈbʌm/US:USA pronunciation: IPA and respellingUSA pronuncation: IPA/bʌm/ ,USA pronunciation: respelling(bum)

Inflections of 'bum' (adjadjective: Describes a noun or pronoun--for example, "a tall girl," "an interesting book," "a big house."):
adj comparative
adj superlative
Inflections of 'bum' (v): (⇒ conjugate)
v 3rd person singular
v pres pverb, present participle: -ing verb used descriptively or to form progressive verb--for example, "a singing bird," "It is singing."
v pastverb, past simple: Past tense--for example, "He saw the man." "She laughed."
v past pverb, past participle: Verb form used descriptively or to form verbs--for example, "the locked door," "The door has been locked."
WordReference Collins English Usage © 2020
‘bottom’ and ‘behind’
Your bottom is the part of your body that you sit on. You can use bottom in conversation and in most kinds of writing.
If she could change any part of her body, it would be her bottom.
Speakers of American English usually say behind rather than ‘bottom’.
My behind ached from cycling all day.
In formal writing, you refer to this part of your body as your buttocks.
He strained the muscles on his shoulders and buttocks.
‘bum’ and ‘butt’
In conversation, some British speakers say bum instead of ‘bottom’, and some American speakers say butt. It is best to avoid both these words as many people think they are impolite.
'bum' also found in these entries (note: many are not synonyms or translations):
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