Metonymic merging of grammatical number

Two good examples of collective nouns are "team" and "government", which are both words referring to groups of (usually) people. Both "team" and "government" are count nouns. (Consider: "one team", "two teams", "most teams"; "one government", "two governments", "many governments"). However, confusion often stems from the fact that plural verb forms can often be used with the singular forms of these count nouns (for example: "The team have finished the project"); and, conversely, singular verb forms can often be used with nouns ending in "-s" that were once considered plural (for example: "Physics is my favorite academic subject"). This apparent "number mismatch" is actually a quite natural and logical feature of human language, and its mechanism is a subtle metonymic shift in the thoughts underlying the words. A good example of such a metonymic shift in the singular-to-plural direction is the following sentence: "The team have finished the project." In that sentence, the underlying thought is of the individual members of the team working together to finish the project. Their accomplishment is collective, and the emphasis is not on their individual identities, yet they are at the same time still discrete individuals; the word choice "team have" manages to convey both their collective and discrete identities simultaneously. A good example of such a metonymic shift in the plural-to-singular direction is the following sentence: "Mathematics is my favorite academic subject." The word "mathematics" may have originally been plural in concept, referring to mathematic endeavors, but metonymic shift—that is, the shift in concept from "the endeavors" to "the whole set of endeavors"—produced the usage of "mathematics" as a singular entity taking singular verb forms. (A true mass-noun sense of "mathematics" followed naturally.) In British English, it is generally accepted that collective nouns can take either singular or plural verb forms depending on the context and the metonymic shift that it implies. For example, "the team is in the dressing room" (formal agreement) refers to the team as an ensemble, whilst "the team are fighting among themselves" (notional agreement) refers to the team as individuals.

In American English, collective nouns usually take singular verb forms (formal agreement). In cases where a metonymic shift would be otherwise revealed nearby, the whole sentence may be recast to avoid the metonymy. (For example, "the team are fighting among themselves" may become "the team members are fighting among themselves" or "the team is fighting [period]".) See American and British English differences - Singular and plural for nouns.