It is interesting how food and cooking terms can evolve over a few hundred years. The earliest reference we can find to frangipane dates from about the mid 1600s, and was applied to a custard tart that included both ground almonds and pistachios in the custard. Since then, it is most often used to refer to an almond-flavored pastry cream, but, like you, we have found a reference to a vanilla-flavored pastry cream without almonds also called frangipane. We have found a pastry shell itself that goes by the name, which may be stuffed with a savory filling rather than sweet. Finally, it can be a gooey, savory paste, used to stuff meats or fish before cooking.

Given all those choices, we vote for the almond-flavored pastry cream, and intend never to use the word for anything else! Nowadays, it is mostly spelled frangipane or frangipani.