v.1. To fill something up with something that it carries: We'll leave as soon as we finish loading up the car with the bags. Let's load the van up and get going.
2. load up on To gather and store a supply of something; stock up on something: I loaded up on shampoo because the store was having a sale.
3. load up on To become drunk or intoxicated. Used in the passive: That guy is loaded up on vodka.