On is the French indefinite subject pronoun, used mainly in informal French. It literally means "one," as in "One would think...." But it is usually used as an informal replacement for various other pronouns. Read this lesson to learn how to use on and discover the grammatical debate surrounding it.
More: French pronouns | Indefinite French
More: French pronouns | Indefinite French
Comments
In theory, “on” is supposed to be neutral but, in practice, usage tends to favor the agreement whenever a specific subject is implied.