Learn English – term for words that have identical singular and plural forms


Is there a term for nouns that have identical singular and plural forms? For example,

  • sheep
  • fish
  • glasses
  • aircraft/spacecraft


Best Answer

According to Wikipedia, some of these are called defective nouns:

Some nouns have no singular form. Such a noun is called a plurale tantum.

For example, glasses, pants, and scissors are all defective nouns because they have no singular form. As these are plurale tantum, the opposite is singularia tantum--nouns with no plural form.

However, examples like sheep and fish are simply irregular plurals.