By the 1500s, galleons were taking cargo across oceans all over the world. Galleons were huge sailing ships.

Which sentence combines these two sentences with an appositive phrase?

By the 1500s, galleons, huge sailing ships, were taking cargo across oceans all over the world.

The second sentence defines a galleon. To combine the two sentences, an appositive phrase is necessary in order to insert the definition of galleon without creating a run-on. Appositive phrases are used to define or clarify a noun. They are typically surrounded by commas. Often an appositive phrase can be erased without damaging the meaning or grammatical structure of the sentence. Another example of an appositive phrase is: Jim, my brother, is happy. The appositive phrase "my brother" explains who Jim is.