Where does “motu proprio” come from?

motu proprio (Medieval Latin) comes from Latin prōprius — appropriate to oneself: (one's) proper, (one's) own.

Ancestry of “motu proprio”, step by step

StepLanguageWordMeaning
1Latinprōpriusappropriate to oneself: (one's) proper, (one's) own
Every word from Latin prōprius