Drop something off - Idiom

1) Drop off – similar to fall 
The boys dropped stones off the cliff 

2) Drop off – fall asleep 
I dropped off while watching TV last night

3) Drop off- gradually decline/ become less
Sales dropped off at the end of the month

4) Drop off- stop somewhere for someone
Could you drop me off at the station?

5) Drop off- stop and give something to someone, To deliver something to some place
Could you drop this letter off at the post office for me?Drop those DVDs off at the video store on your way home. We'll drop off the gifts at your house later [*] [**]