Natura Brevium
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
The name of an ancient collection of original writs, accompanied with brief comments and explanations, compiled in the time of Edward III. This is commonly called "Old Natura Brevium," (or "O. N. B.,") to distinguish it from Fitzher-bert's Natura Brevium, a later work, cited as "F. N. B.," or "Fitzh. Nat Brev,"