The word "sup" is a colloquial term that means to have a meal or to eat. It's often used informally in conversations. It can also function as a greeting, originating from the phrase "What's up?" or "What's going on?"
The word "sup" comes from the Old English "sūpan," meaning "to sip" or "to take a little." It has evolved into its modern usage as a casual term for eating or dining.