1. Phrase. Said when handing something over to someone or doing a favour to them, usually to draw the recipient's attention to the exchange; equivalent to “thank you” when receiving something.
2. adv. (location) To this place; used in place of the more dated hither.
Please come here.
3. adv. (abstract) In this context.
Derivatives can refer to anything that is derived from something else, but here they refer specifically to functions that give the slope of the tangent line to a curve.