Meaning of yield in math

What is the meaning of yield in math? In math, yield is the amount of money expressed as a percent that you make from an investment usually each year.  

A yield can come from investing money in a saving account, a certificate of deposit(CD), a share, or a stock.

A couple of examples showing what the yield is in math

Example #1

You put $20,000 in a saving account and every year the bank gives you $1000. What is the yield?

1000 / 20000 = 0.05

0.05 as a percent is 5%

The yield is 5%

Example #2

You put $15000 in a saving account and every year the bank gives you $300. What is the yield?

300 / 15000 = 0.02

0.02 as a percent is 2%

The yield is 2%