Tighten/ˈtaɪtn/ Definition 1 of 4Pro Tip 1/2Physical Tightening Used when physically securing an object, like closing lids or tying ropes. Make sure to tighten all the bolts when assembling the furniture. Pro Tip 2/2Prevent Leakage Often implies creating a seal to stop liquids or gases from escaping. Tighten the valve to prevent the gas from leaking out.