Wage theft is when your employer steals from you. Under California law, there are very clear obligations for when, why, and under what circumstances your employer must pay you.
There are meal breaks and there are rest breaks. But, unfortunately, not all employers honor those obligations, and they try to squeeze extra time out of each individual employee by stealing money from you.
In effect, there’s overtime pay that you’re entitled to, there’s double-time pay, and sometimes, employers just don’t pay what they’re obligated to pay.