diminutive

noun
  1. 1

    (grammar) A word form expressing smallness, youth, unimportance, or endearment.

    โ€œBooklet, the diminutive of book, means โ€˜small bookโ€™.โ€

adjective
  1. 1

    Very small.

  2. 2

    Serving to diminish.

  3. 3

    (grammar) Of or pertaining to, or creating a word form expressing smallness, youth, unimportance, or endearment.

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