Lat. The custom of merchants , the same with lex meroatoria. Consuetudo contra rationem intro- ducta potius usurpatio quam consuetudo appellari debet. A custom introduced against reason ought rather to be called a “usurpation” than a “custom.” Co. Litt. 113. Consuetudo debet esse certa; nam in- certa pro nulla habetur. Dav. 33. A custom should be certain; for an uncertain custom is considered null. Consuetudo est altera lex. Custom Is another law. 4 Coke, 21. Consuetudo est optimus interpret le- gnm. 2 Inst. 18. Custom is the best expounder of the laws. Consuetudo et communis assuetudo vincit legem non scriptam, si sit spe- cialis; et interpretatur legem scriptam, si lex sit generalis. Jenk. Cent. 273. Custom and common usage overcomes the unwritten law , if it be special; and interprets the written law , If the law be general. Consuetudo ex certa causa rationablli nsitata privat communem legem. A custom, grounded on a certain and reasonable cause, supersedes the common law. Litt.