notice

verb:to become aware of or observe something
- She noticed a faint smell of gas coming from the kitchen.
noun:the fact of observing or paying attention to something
- The change in his behavior did not escape her notice.
noun:an announcement or sign used to inform or warn people
- There was a notice on the door stating the office was closed.
noun:a formal announcement or warning of something, especially of the termination of an agreement
- He received a two‑week notice before his employment was terminated.