Merriam-Webster Collegiate Dictionary - vernacular

 I. adjective  Etymology: Latin vernaculus native, from verna slave born in the master's house, native  Date: 1601  1.  a. using a language or dialect native to a region or country rather than a literary, cultured, or foreign language  b. of, relating to, or being a nonstandard language or dialect of a place, region, or country  c. of, relating to, or being the normal spoken form of a language  2. applied to a plant or animal in the common native speech as distinguished from the Latin nomenclature of scientific classification the ~ name  3. of, relating to, or characteristic of a period, place, or group; especially of, relating to, or being the common building style of a period or place ~ architecture  • ~ly adverb  II. noun  Date: 1661  1. a ~ language, expression, or mode of expression  2. the mode of expression of a group or class  3. a ~ name of a plant or animal