In the demonstratives and in some indefinite pronouns, there is a trace of the neuter gender of Latin. For example, todo and esse are used with masculine referents, toda and essa with feminine ones, and tudo and isso when there is no definite referent. Thus todo livro "every book" and todo o livro "the whole book"; toda salada "every salad" and toda a salada "the whole salad"; and tudo "everything"; etc.:
