1. The process of deducting one number from another number to determine the difference.
2. Hist. The act of neglecting a duty or service that one party owes to another, esp. one that arises out of land tenure.
“Subtraction, which is the fifth species of injuries affecting a man’s real property, happens, when any person who owes any suit, duty, custom, or service to another, withdraws or neglects to perform it. It differs from a disseisin, in that this is committed without any denial of the right, consisting merely in non-performance; that strikes at the very title of the party injured, and amounts to an ouster or actual dispossession. Subtraction however, being clearly an injury, is remediable by due course of law: but the remedy differs according to the nature of the services; whether they be due by virtue of any tenure, or by custom only.” 3 William Blackstone, Commentaries on the Laws of England 230 (1768).
