Black's Law Dictionary (2nd edition)dictionaries

Ac Si

(Lat As if.) Townsh. Pl. 23, 27. These words frequently occur in old English statutes. Lord Bacon expounds their meaning in the statute of uses: “Tbe statute gives entry, not simpliciter, but with an ac Bi." Bac. Rend. Uses, works, iv. 195

Source: Black's Law Dictionary 2nd Ed (1910)