Knight-Service
Defined in 2 dictionaries — Black's (1910), Stimson (1881)
Black's Law Dictionary
Henry Campbell Black, M.A. · 1910
A species of feudal tenure, which differed very slightly from a pure and perfect feud, being entirely of a military nature; and it was the first, most universal, and most honorable of the feudal tenures. To make a tenure by knight-service, a determinate quantity of land was necessary, which was calied a "knight's fee," (feodum militare,) the measure of which was estimated at 680 acres. Co.. Litt. 69a; Brown.
Glossary of Technical Terms, Phrases, and Maxims of the Common Law
Frederic Jesup Stimson · 1881
Tenure iu chivalry; y. by military, uncertain services; or by paying