To take over means to gain control of something or to assume responsibility for something that someone else was handling. When a substitute teacher takes over your class, they step in to lead the lessons while your regular teacher is away. When a relay runner takes over from a teammate, they grab the baton and continue the race.

The phrase appears in many contexts. A new manager might take over a struggling department and turn it around. In a group project, if one person isn't pulling their weight, another student might need to take over their tasks. Companies take over other companies by purchasing them and assuming control of their operations.

Sometimes take over describes something spreading or dominating completely. Weeds can take over a garden if left unchecked. A catchy song might take over the radio, playing everywhere you go. In this sense, the phrase suggests something expanding beyond its original boundaries until it fills or controls a space.

The phrase can also describe a temporary arrangement. When you take over stirring the soup while your parent answers the phone, you're helping out briefly. But when a dictator takes over a country, that suggests a more permanent and forceful seizure of power. Context tells you whether someone is taking over helpfully, forcefully, or simply as part of a planned transition.