brad; double-pointed nail
A small nail with a very small head, used for fine woodworking or where the nail head should be inconspicuous. Also refers to a nail pointed at both ends.
Using brads for the craftwork gives a clean finish.
Brads have small heads, so they are inconspicuous when driven in.
Compound of 切り (kiri, 'cut') and 釘 (kugi, 'nail'), referring to a nail that is cut or shaped with a minimal head.