Phrasal verb
be on
Meanings
To be operating or functioning (for lights, devices, machines, systems).
To be scheduled to happen or currently happening (for events, shows, meetings, activities).
To be actively pursuing, targeting, or criticizing someone (often in informal speech).
Definition
To be on means to be operating or functioning, or to be scheduled to happen.
"Be on" is used to say that a device, light, or system is operating. It can also mean that an event or activity is scheduled or currently happening. In some situations, it can describe a person actively trying to achieve something or strongly criticizing someone.
Examples
- The air conditioner is on, so the room feels cooler.
- Is the meeting still on for Friday afternoon?
- Her favorite comedy is on at eight, so she wants to get home early.
- After the mistake, the manager was on him all morning.
- The porch light was on when they arrived.
Common mistake
Learners often say "is open" when they mean "is on" for devices (e.g., a light is on, not open).
More phrasal verbs
- go on To go on means to continue or keep happening.
- carry out To carry out something means to do it or complete it, especially a plan, task, or instruction.
- set up To set up means to arrange or prepare something so it is ready to use or happen.
- pick up “Pick up” most commonly means to collect someone or something from a place, usually by going there.
- go back To go back means to return to a place, time, or earlier situation.