1. people who test products, systems, or materials to evaluate their quality or performance
2. small samples of products, especially cosmetics or food, given to customers to try
3. devices or instruments used to test or measure something

Examples

• The software testers found several bugs before the product launch.
• Quality testers inspect each item on the assembly line.
• The cosmetics counter offered free testers of the new lipstick.
• Food testers at the grocery store let customers sample the cheese.
• The electricians used voltage testers to check the wiring.
• Battery testers help determine if old batteries still work.
• Game testers play video games to find glitches and problems.