Definition of 'Buck'
1. An informal reference to one dollar.
2. An informal term for one hundred dollars.
3. Trader's slang for a million dollars. Wall Street jargon sometimes differs from everyday usage.
4. An informal term for money.
The term "buck" may trace its origins to the days when deerskins (buckskins) were commonly traded.
Investopedia explains 'Buck'
"Buck" is used in numerous colloquial expressions:
-"Bang for your buck," meaning value for the amount of money spent.
-"Break the buck," referring to the net asset value of a money market fund falling below one dollar
-"Make a quick buck," meaning to earn money in a short period of time and with minimal effort
Other American slang terms for money include green, scratch, moolah, cheddar, bacon and dough.