fastness

/หˆfรฆstnษ™s/

IPA: /F AE1 S T N AH0 S/

noun
  1. 1

    A secure or fortified place; a stronghold, a fortress.

  2. 2

    The state of being fast.

  3. 3

    The ability of a dye to withstand fading.

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