1.  dark thick substance obtained from wood and other organic substances (used in protective coatings and sealants); sailor (ınformal). smear or cover with tar, cover with asphalt, cover with pitch. tartar , n. [abbrev. from tarpaulin.] a sailor; a seaman. [colloq.]tar tar, n. [oe. terre, tarre, as. teru, teoru; akin to d. teer, g. teer, theer, icel. tjara, sw. tj?ra, dan. ti?re, and to e. tree