dolmens

/D AA1 L M EH0 N Z/
noun
  1. 1

    A prehistoric megalithic tomb consisting of a capstone supported by two or more upright stones, most having originally been covered with earth or smaller stones to form a barrow.

  2. 2

    More generally, any megalithic tomb, including passage graves and wedge tombs.

Source: https://en.wiktionary.org/wiki/dolmen, https://en.wiktionary.org/wiki/dolmens