A small metal spike with a flattened end driven into wood with a hammer, to join and hold together, or used as a peg or hook.
Upholstery nails ( these are the decorative ones as opposed to the working tacks) are used to cover raw fabric edges, to protect vulnerable points and also by design choice or placement to create or confirm a certain style.
These nails, or studs, are usually domed, but come in almost any profile, shape and colour, and can either disappear in the fabric design or stand out against it. When we haven’t been able to find the right colour, we’ve been known to paint nails ourselves to achieve the right effect.