Many historians focus primarily on authors' “intended meanings.” Yet all textual interpreters, including historians, need a second kind of meaning. I call this idea “extended meaning,” a new name for an old idea: “P means Q” is the same as “P logically implies Q.” Extended and intended meaning involve different kinds of understanding: even if we grasp exactly what authors meant, we miss something important if we overlook their errors, for example. Crucially, extended and intended meaning are not alternatives: just as some parts of texts cannot be understood without historical analysis, so too some parts of texts cannot be understood without philosophical analysis. Indeed, some historians are adept at using extended meanings to recover intended meanings. But the failure to make this explicit has led many historians to undervalue philosophical analysis. This article thus applies the idea of extended meaning to three practical questions: whether we can deviate from authors' intended meanings, whether we can use anachronisms, and how we can use extended meanings to recover intended meanings. The idea of extended meaning thus strengthens our theoretical foundations and offers valuable practical tools.