mi·a·ro·lit·ic \|mēərō|lid.ik\adjective Etymology: International Scientific Vocabulary miaro- (from Italian dialect miarolo granite with small cavities) + -litic 1.of igneous rock: characterized by irregular cavities into which well-formed crystals project < miarolitic structure > < miarolitic granites > 2.of a cavity: having an irregular form into which such crystals project