1. "Month": This is the most common usage of "mo" as an abbreviation of "month." For example, "I have a doctor's appointment next mo."
2. "Money": "Mo" is sometimes used casually as shorthand for "money." For example, "I don't have the mo to buy a new car right now."
3. "More": "Mo" can be used as a slang abbreviation of "more." For example, "They've been together for mo than five years."
4. "Missouri": "MO" is the two-letter abbreviation for the state of Missouri in the United States. For example, "She's from St. Louis, MO."