Why is the ninth month called September?
1640s, "practicable," from operate + -able, or else from Late Latin operabilis. Surgical sense, "capable of treatment by operation," recorded by 1904. Related: Operability.
operable op·er·a·ble (ŏp'ər-ə-bəl, ŏp'rə-)adj. Being treatable by surgical operation with a reasonable degree of safety and chance of success.