cast in stone

Idioms and Phrases

Also, etched in stone . Definite, fixed, as in We may choose to stay longer—our plans aren't cast in stone , or When Carl sets an agenda you can safely assume it's etched in stone . Both expressions allude to sculpture, with the first, from the early 1500s, using the verb cast in the sense of pouring and hardening some material into a final form, and the second cutting or corroding a permanent design.