HETEROGENEOUS NOUNS, one of the three variations in irregular nouns; or such as are of one gender in the singular number, and of another in the plural.—Heterogeneous, under which are comprehended mixed nouns, are sixfold. 1. Those which are of the masculine gender in the singular number, and neuter in the plural; as, hic tartarus, hec tartara. 2. Those which are masculine in the singular number, but masculine and neuter in the plural; as, hic locus, hi loci et hec loca. 3. Such as are feminine in the singular number, but neuter in the plural; as, hec carbasus, et hec carbasus. 4. Such nouns as are neuter in the singular number, but masculine in the plural; as, hoc caelum, hi caeli. 5. Such as are neuter in the singular, but neuter and masculine in the plural; as, hoc rostrum, hi rostri, et hec rostra. And, 6. Such as are neuter in the singular, but feminine in the plural number; as, hoc epulam, hec epula.