1. a room or building equipped for scientific experiments, research, or teaching
2. a place providing opportunity for experimentation, observation, or practice in a field of study

Examples

• The students conducted their chemistry experiments in the lab.
• She works as a researcher in a medical lab.
• The computer lab is open until midnight.
• We need to finish our lab report by Friday.
• The biology lab has new microscopes this year.
• He spends most of his time in the physics lab.
• The language lab helps students practice pronunciation.