Meat, usually pork, simmered for a long time in a dark broth of soy sauce, rock sugar and spices such as star anise. Tender and salty-sweet; served sliced with some of the broth, or over rice.
卤 as a cooking verb means to slow-simmer in soy sauce, rock sugar, and spices (star anise, cinnamon, bay). The braise liquid itself is 卤水, and it's reused and aged. Some shops have 老卤 running for decades.