ホルンフェルスホルンフェルスMeanings1nounhornfelsA fine-grained metamorphic rock formed by contact metamorphism. Technical geological term.from German Hornfelsホルンフェルスは接せっ触しょく変へん成せい作さ用ようで形けい成せいされる岩がん石せきです。Hornfels is a rock formed by contact metamorphism.