2 [count] : money that is spent and that is more than the amount earned or received
The company's losses for the year were higher than expected.
profits and losses
They took a loss on the deal. [=the deal cost them money; they lost money on the deal]
The business is operating at a loss. [=the business is spending more money than it is earning]
They sold the property at a (considerable) loss. [=for less than they paid for it]
— see also at a loss (below)