No, it doesn’t mean we cover them in plastic.
Laminating in the kitchen refers to folding buttery pastry dough to create flaky layers–think puff pastry and croissants. As usual, it’s all about the butter. We want it cold and in thin pieces so that the dough has alternating thin sheets of dough and butter. The fat separates the dough sections and prevents them from interacting, and as the biscuit hits the hot oven, the water in the butter evaporates and puffs up the dough just a little bit. Butter serves both as a boundary between dough layers and as a leavener when it turns to steam in the oven, and that combination creates the gorgeous, flaky layers.
If this whole discussion makes you think about pie, then a) please make this one and invite me over, and b) you’re exactly right. Both doughs rely on thin layers of butter to create a flaky texture, but two main differences distinguish them. First, pie doughs have small, irregular pieces of butter while the folding step in laminated dough creates sheets of butter that stretch across the whole pastry. Essentially, pie crust is flaky on a smaller scale because the essential bits of butter are smaller. Second, a good pie crust has very little gluten formation to keep it tender instead of tough, but laminated doughs need some gluten development to function. When the water from the butter expands into steam, it pushes on the dough. A strong dough can stretch to accommodate it, but a weak dough would just break–working the flour just enough to strengthen the dough will make sure your layers stay intact.