Buttercream - A frosting made from whipped butter (we use Earth Balance nondairy butter), powdered sugar, vanilla, and milk or cream (we use soy or almond milk). It is sweet and creamy and can be adapted to just about any flavor.
Ganache - A rich, thick combination of chocolate, butter, and heavy cream. it can be used as a filling or whipped to make a decadent frosting. It comes in dark or white chocolate.
Tier - Some people get layers confused with tiers. Wedding cakes are usually several tiers--individually sealed cakes of different sizes, stacked on top of one another. Each tier is usually made of 2-4 layers, with filling between each layer.
Fondant - Fondant is a decorative medium made of sugar. It is entirely edible and can be rolled to cover cakes for a satin smooth finish, or can be sculpted like clay to create flowers, details, figurines, etc.
Gumpaste - The same thing as fondant, but with tylose powder added to make it dry hard like porcelain. It is also entirely edible and has no significant flavor difference from fondant.
Doweling - Cakes are heavy. When you stack a cake on top of another, it needs support to make sure it doesn't collapse the cake beneath it. When cakes gets stacked, each cake sits on its own cakeboard, and is supported by paper or wooden dowels, which are inserted into the tier below it. When cutting your cake, simply start from the top. When all the cake from one tier has been served, remove the empty cakeboard and remove the dowels from the underlying tier. Tall cakes may also have a dowel running the entire height of the cake, in the very center. This dowel or skewer keeps the cake from shifting or sliding during transport.
Nonpareils - Small sugar beads. They are colored, pearlized, or metallic, and are edible.
Royal icing - Icing traditionally made from eggwhites or meringue powder (we use egg-free Aquafaba), powdered sugar, and water. It dries hard and brittle and can be used for a wide variety of decorating.