英英辞典みろや。ほんとにひろゆき留学してたのか？
Cambridge Advanced Learner's Dictionary
deposit (STORE MONEY) Show phonetics
verb [T]

to pay someone
a sum of money　←
when you make an agreement with them to pay for or buy something,
which either will be returned to you later, if the agreed arrangement is
kept, or which forms part of the total payment:

2 a sum of money which is given in advance as part of a total payment for something:
The shop assistant says if I leave £10 as a deposit, they'll keep the dress for me.
We paid/put a deposit of £10 000 on the house, and paid the balance four weeks later.

3 a sum of money which you pay when you rent something, and which is returned to you when you return the thing you have rented: