Yield, quite simply - the cash return you get from leasing your property, expressed as a percentage.
A property is valued at $500,000
The rent you receive is $500 / week
$500 x 52 weeks = $26,000 per year
divided by the property value $500,000 x 100
= 5.2% yield
Yield is a simple and quick way to start a property analysis. You will often see yield advertised in property adverts, or relating to particular suburbs or property types.
Yield also changes during the property cycle, for example in Sydney presently property values have risen so fast that the yield is relatively low - whereas properties in Brisbane typically offer a better return, or yield, because the price growth has been moderate. This in itself can be a catalyst for the cycle to turn; with investors flocking to suburbs featuring higher yield - which in turn can push up prices & reduce the relative yield for those coming in later.
It isn't the complete picture as it doesn't take into consideration growth history or projections, nor the expenses and risks relating to the property but an experienced investor uses this as a starting point and its an easy place for you to start too.