1. noun An abbreviation for "point of sale," referring to the place where a sales transaction takes place. We need to get our POS system up and running before the store opens in an hour!

2. noun, rude slang An abbreviation for "piece of shit," a derisive term for someone or something that one considers worthless or contemptible. What do I want this POS for? It's a table with two and a half legs! Only a real POS would use racist terms like that.

3. adjective, rude slang An initialism for "piece of shit," meaning utterly worthless, contemptible, or inferior. This POS computer keeps crashing on me! Sally's POS boyfriend just tried to sell me dope.