hacek

/HH AA1 CH EH0 K/
noun
  1. 1

    A caron; a diacritical mark (ˇ) usually resembling an inverted circumflex, but in the cases of ď, Ľ, ľ, and ť resembling a prime (′) instead.

Source: https://en.wiktionary.org/wiki/h%C3%A1%C4%8Dek, https://en.wiktionary.org/wiki/hacek