D defs.my
Entry 1 sense Webster, 1913

Flagstone

/flăg'-stōnˌ/ · Flag·stone · IPA /ˈflæɡˌstoʊn/
01 n. A flat stone used in paving, or any rock which will split into such stones. See Flag, a stone.
  1. 1.
    A flat stone used in paving, or any rock which will split into such stones. See Flag, a stone. See: Flag