Darbage

An investment is a calculated placement of resources with the expectation of at least a certain amount of fair return.

The placement of resources with a return based on odds is also an investment. Those returns are less certain.

However the placement of resources based on sheer luck is gambling and while those returns are rare, they do still occur.

For example, casino owners invest, while their patrons gamble, but the inevitably the house always wins.

When you have reached the point where you have lost any expectation at all of a return  on your resources and you still keep putting in, at that point you're just throwing it away.