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 six-fold. 1. Those which are of the masculine gender in the singular number, and neuter in the plural; as hic tartarus, hæc tartara. 2. Those which are masculine in the singular number, but masculine and neuter in the plural; as hic locus, hi loci, & hæc loca. 3. Such as are feminine in the singular number, but neuter in the plural; as hæc carbafus, & hæc carbasa. 4. Such nouns as are neuter in the singular number, but masculine in the plural; as hoc cælum, hi celi. 5. Such as are neuter in the singular, but neuter and masculine in the plural; as hoc rastrum, hi rastris, & hæc rastra; and, 6. Such as are neuter in the singular, but feminine in the plural number; as hoc epulum, hæc epule.