instars

/IH0 N S T AA1 R Z/
noun
  1. 1

    Any one of the several stages of postembryonic development which an arthropod undergoes, between molts, before it reaches sexual maturity.

  2. 2

    An arthropod at a specified one of these stages of development.

  3. 3

    (by extension) A stage in development.

Source: https://en.wiktionary.org/wiki/instar, https://en.wiktionary.org/wiki/instars