In addition to normal singular nouns, Adûnaic had some collective nouns that represented all objects of a particular kind, similar to the class plural of Sindarin, but not as a formal inflection. These collective nouns also had corresponding singular nouns to represent a single instance of the class:

• kulub “roots (as a category of plants)” vs kulbu “a single root” (SD/431).
• gimil “(all) stars” vs gimli “a single star” or igmil “a star-shaped figure” (SD/427).

The collective nouns could only be declined in the singular, whereas their singular equivalents could be declined normally. The plural of the singular forms would be used for a specific group instead of all members of the class: gimli “a star” → gimlî “some stars” vs. gimil “all stars” (SD/427).

These collective nouns were not a formal inflection by the time of Classical Adûnaic, but may have been a fossilized form of some archaic inflection from Primitive Adûnaic.