whom

/huหm/

IPA: /HH UW1 M/

pronoun
  1. 1

    (interrogative) What person or people; which person or people.

  2. 2

    (relative) Used to refer to a previously mentioned person or people.

    โ€œHe's a person with whom I work. (defining)โ€

  3. 3

    (fused relative, archaic outside set patterns) The person(s) whom; whomever.

    โ€œTo whom it may concern, all business of John Smith Ltd. has now been transferred to Floggitt & Runne.โ€

Source: https://en.wiktionary.org/wiki/whom