As investors use the term, total return is the change in value of an investment over a given period, assuming reinvestment of any dividends or capital gain distributions, expressed as a percentage of the initial investment.  The total return includes dividends, capital gains distributions, and the increase in the net asset value of the asset. 
Assets are usually purchased, or equivalently a deposit is made, in hopes of getting a future return, or interest from it. Assets are held to have some recurring, or capital appreciation. Assets are expected to give income, without any work on the asset per se.  Total return is all that is expected to return, assuming it is reinvested and expressed as a percent.
An investor purchases an asset for $100 on 1/1/90. The asset yields $10 of cash flows at the end of one year. After one year, the asset has a market value of $130. The investors total return is thus:
Seen from a cash flow perspective, an asset is something that puts money in your pocket, and a liability is something that takes money out of your pocket.  The word investment originates in the Latin "vestis," meaning garment, or vest, and refers to the act of putting assets into others pockets.