The word "over" is a preposition that can indicate a position above or higher than something else. It can also imply movement or action across or beyond a certain point. Additionally, "over" can express concepts of excess, completion, or duration. For example, if you say "The bird flew over the tree," it means the bird moved above the tree.
The word "over" originates from Old English "ofer," which means "over, above, or across." It is related to the Gothic word "ubair" and the German "über," both of which convey similar meanings.