Large means the size of an item, such as clothing, that falls between medium and extra-large. If you realize your size has changed from medium to large, it might be time to cut back on the cupcakes.
Something that is above average in size or number can be described with the adjective large. Your large collection of bottle caps, which covers the walls of three rooms in your house, is a perfect example. Large also describes something that covers a broad spectrum or scope. You might love being an American studies major because your classes cover a large range of topics.