What part of speech is ‘in’?

In is primarily classed as a preposition, but it can be classed as various other parts of speech, depending on how it is used:

  • Preposition (e.g., ‘in the field’)
  • Noun (e.g., ‘I have an in with that company’)
  • Adjective (e.g., ‘Tim is part of the in crowd’)
  • Adverb (e.g., ‘Will you be in this evening?’)