The word "apostume" is a rare term used to describe a collection of pus within a cavity in the body. It is spelled a-p-o-s-t-u-m-e and pronounced /əˈpɒstjuːm/. The IPA phonetic transcription breaks this down as follows: the first syllable is pronounced "uh" (schwa sound), followed by "p" (as in pet), "o" (as in top), "s" (as in sit), and "t" (as in take). The second syllable is pronounced "yoo" (as in cute) and "m" (as in map) at the end.
The word "apostume" has its origins in Middle English and comes from the Old French term "apostume" or "postume". This Old French word, in turn, was derived from the Latin term "apostuma", which meant an abscess or swelling. The Latin term "apostuma" itself was derived from the Greek word "apostēma", meaning an abscess or gathering of purulent matter.