Availability means being present, ready, and able to help or participate when needed. When your teacher checks student availability for after-school tutoring, she's finding out who can actually show up. When a doctor has limited availability next week, it means she has only a few open appointment times.

The word combines two ideas: physical presence (being there) and readiness (being able to help). A fire extinguisher might hang on the wall every day, but its true availability depends on whether it actually works when you need it. Your friend might live next door, but if she's always busy with other activities, her availability to hang out is low.

In stores and online shopping, availability describes whether a product is in stock and ready to purchase. “Limited availability” means something might run out soon.

Being available means being accessible and ready when someone needs you. When you tell a friend “I'm available this weekend,” you're offering both your time and your willingness to spend it together.