money、cash、coin与currency这些名词均有“（金）钱”之意。

money : 钱的通称，可以是硬币可以是纸币，也可指用作货币的其它物品。

• to borrow/save/spend/earn money
  借 / 存 / 花 / 挣钱
• How much money is there in my account?
  我的账上有多少钱？
• The money is much better in my new job.
  我的新工作薪水高多了。

cash : 特指立即可以兑现的现金或现款。

• How much cash do you have on you?
  你身上带着多少现金？
• Payments can be made by cheque or in cash.
  支票或现金付款均可。
• Customers are offered a 10% discount if they pay cash.
  顾客若付现金，可获九折优惠。

coin : 指铸造的硬币。

• a euro coin
  欧元硬币
• notes and coin
  纸币和硬币

（拓展学习：熟词僻义 | coin 是一种怎样的创造？）

currency : 指在流通中的货币，是全部流通中通货的总称，也可指纸币。

• trading in foreign currencies
  买卖外汇
• a single European currency
  统一的欧洲货币
• You'll need some cash in local currency but you can also use your credit card.
  你将需要一些当地的货币现金，但也可使用信用卡。