Like the name suggests, side tables are placed beside a piece of furniture, like a sofa or bed, for easy access to things you frequently use. Side tables are usually at the height of the sofa arm or slightly lower, around 18"-20". When people talk about side tables, they might also mention nesting tables, which are essentially just a group of side tables (usually in threes!) in varying dimensions so they can nest within each other. Nesting tables are a good option if space at home is tight, but you want to have the option of additional tables for entertaining when needed.