A plurale tantum (Latin for 'plural only'; pl. pluralia tantum) is a noun that appears only in the plural form and does not have a singular variant for referring to a single object. In a less strict usage of the term, it can also refer to nouns whose singular form is rarely used.
In English, pluralia tantum are often words that denote objects that occur or function as pairs or sets, such as spectacles, trousers, pants, scissors, clothes, or genitals. Other examples are for collections that, like alms, cannot conceivably be singular. Other examples include suds, jeans, outskirts, odds, riches, goods, news, gallows (although later treated as singular), surroundings, thanks, and heroics.