thumbtack
Thumbtack (noun) means a small tack with a slightly rounded head, pressed into place with the thumb to hold light items on a wall or noticeboard. Example: “She pinned the poster up with a thumbtack in each corner.”
How to use thumbtack
Learner’s notesIn plain EnglishA small pin you push in with your thumb to hang things up.
It is the everyday word in Canada and the US.
Fill the gap
Can you complete this real example?
She pinned the poster up with a _____ in each corner.
Etymology
It is a compound of the English words thumb and tack, named for being pushed in with the thumb.