[Latin words ending in -aris, -arius, -arium, or -are, or Old French words ending in -aire or -ier.]
Examples from Latin include altar, bursar, cellar, exemplar, mortar, scholar, and vicar. Examples from Old French include burglar, collar, pillar, poplar, and vinegar. For a few nouns this ending is a variant of -er (see -er1) or -or (see -or1 and -or2), changed by an accident of spelling history: liar, beggar. Other nouns have this ending by chance, often through an origin in some other language: sugar (from Arabic), guitar (Greek), briar (Old English), fulmar (Old Norse), jaguar (Tupi-Guarani). Others, such as sonar and radar, are acronyms. See also -aire and -ary1.