1. (v. t.) To take notice of by appropriate conduct; to conform one's action or practice to; to keep; to heed; to obey; to comply with; as, to observe rules or commands; to observe civility.

2. (v. t.) To be on the watch respecting; to pay attention to; to notice with care; to see; to perceive; to discover; as, to observe an eclipse; to observe the color or fashion of a dress; to observe the movements of an army.

3. (v. t.) To express as what has been noticed; to utter as a remark; to say in a casual or incidental way; to remark.

4. (v. i.) To take notice; to give attention to what one sees or hears; to attend.

5. (v. i.) To make a remark; to comment; -- generally with on or upon.