1. to attach or secure something firmly in place
Usage: third person singular present tense of ‘fasten’
2. to close or lock something using a fastener
Usage: third person singular present tense of ‘fasten’

Examples

• She fastens her seatbelt before starting the car.
• He fastens the rope to the dock with a strong knot.
• The carpenter fastens the boards together with screws.
• Mom fastens the baby’s diaper carefully.
• The sailor fastens the sail to the mast.
• She fastens her necklace around her neck.
• The worker fastens the safety harness before climbing.