fasten
/ˈfæsn̩/ /Brit ˈfɑːsn̩/
verb
fastens; fastened; fastening
[+ obj] :to attach (something) or join (two things or two parts of something) especially by using a pin, nail, etc.
[no obj] of parts of something :to become attached or joined
[+ obj] :to put something in a position or location in such a way that it will not move
to close and lock (something, such as a window or door) [+ obj]
to grip and hold something with (your hand, teeth, etc.) [+ obj]
fasten on
[phrasal verb]
fasten (something) on (something) or fasten on (something) :to direct (something, such as your eyes or attention) to (something)
fasten onto
[phrasal verb]
fasten onto (something) :to grip and tightly hold (something)