ex post facto

Where does the word "ex post facto" come from? It comes from Latin ex post facto, and was adopted directly into English (1600s).

Ex post facto’s story begins in Latin: ex post facto meant “from after the fact.” From after the fact, from ex (from) post (after) and factum (fact, deed). It reached English by 1600s as ex post facto. The US Constitution forbids ex post facto laws. Today, ex post facto means done, made, or applying retroactively, after the fact.

1. Stage 1 · Latin · ancient ex post facto "from after the fact", from after the fact, from ex (from) post (after) and factum (fact, deed).
2. Stage 2 · English · 1600s ex post facto "done or applying retroactively", the US Constitution forbids ex post facto laws.