Down is one of the most commonly used words in English with multiple meanings:
1. As an adverb: toward or in a lower place or position
2. As a preposition: from a higher to a lower position
3. As an adjective: feeling sad or depressed
4. In sports: not functioning or available
5. Slang: to be okay with something ("I'm down for pizza")
6. In technology: not working ("The server is down")