What is annuity kind of cash flow?

An annuity is a kind of investment in which the investor
gets a guaranteed return each year (or each of any given period).  Therefore, the cash
flow in an annuity is constant -- it follows a given pattern
consistently.

In annuity cash flow, the investor always
gets a specified payment at a specific interval.  The payment is always the same and
there is always the same interval between one payment and the
next.

For example, then, buying stock does not give a
person an annuity cash flow.  The firms in which you buy stock may give dividends at
fixed intervals, but the dividends are not likely to be the same every time.  They will
go up and down as the firm's fortunes change.