The word fold has several related meanings:

1. To bend something over on itself, like when you fold a piece of paper in half to make a card, or fold your clothes before putting them in a drawer. When you follow origami instructions, you're making precise folds to transform flat paper into cranes, boats, or other shapes. A fold can also be the crease or line that forms where something bends: the folds in a curtain, or the folds in fabric.
2. To close or collapse something by bending its parts together. You might fold up a lawn chair for storage, fold down the back seats in a car to make room for cargo, or fold your hands in your lap during a presentation. Things that are foldable can be made compact this way.
3. To mix ingredients gently in cooking by lifting and turning the mixture rather than stirring vigorously. When a recipe says to fold in the blueberries, you're carefully combining them without crushing them or deflating the batter.
4. To give up or quit, especially in card games or business. In poker, when your cards are weak, you fold by laying them down and sitting out that round. A business that can't compete might fold, meaning it closes permanently.