A hypothesis is a proposed explanation for a phenomenon or a prediction about the outcome of an experiment. It is a statement that can be tested through experimentation and observation. In an experiment, the hypothesis is typically stated as an "if-then" statement, where the researcher predicts that if a certain condition is met, then a specific outcome will occur. The hypothesis guides the research process by providing a clear direction for the experiment and helping to determine the variables that need to be tested. It is important for a hypothesis to be testable, falsifiable, and based on existing knowledge or observations.