fasten (fastens 3rd person present) (fastening present participle) (fastened past tense & past participle )
1 verb When you fasten something, you close it by means of buttons or a strap, or some other device. If something fastens with buttons or straps, you can close it in this way.
(=do up)
She got quickly into her Mini and fastened the seat-belt... V n
2 verb If you fasten one thing to another, you attach the first thing to the second, for example with a piece of string or tape.
(=attach)
There were no instructions on how to fasten the carrying strap to the box... V n prep/adv