Select the option that can be used as a one-word substitute for the given group of words.

A word that has the same or nearly the same meaning as another word in the same language.

Synonym

The term "synonym" refers to a word that has the same or nearly the same meaning as another word in the same language. It represents a word or phrase that can be used interchangeably with another word to convey a similar or equivalent meaning. In the given group of words, "a word that has the same or nearly the same meaning as another word in the same language," the word "synonym" precisely captures the concept of words with similar meanings.

"Metonymy" refers to a figure of speech where one word is substituted for another word that is closely associated with it. It does not represent the concept of words with similar meanings in the same language.

"Antonym" refers to a word that has the opposite meaning of another word. It indicates a relationship of opposition or contrast, rather than similarity.

"Toponym" refers to a place name or a word derived from a place name. It is unrelated to the concept of words with similar meanings.

Therefore, "Synonym" is the most appropriate one-word substitute for the given group of words as it directly represents a word with the same or nearly the same meaning as another word in the same language.