Modns decimandi
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
In ecclesiastical law
A manner of tithing; a partial exemption from tithes, or a pecuniary composition prescribed by immemorial usage, and of reasonable amount; for it will be invalid as a rank modus if greater than the value of the tithes in the time of Richard I. Stim. Law Gloss.