Nail: Driven by force; holds by friction. Common nails have thick shanks; finishing nails have small heads (hidden in wood). Sized in pennies (d) — a 10d nail is ~3 inches long.
Double-headed nail: Two heads on the shank; driven to the lower head so the upper is exposed for easy removal. Used for temporary formwork and scaffolding.
Screw: Helical threads hold by thread engagement; holds better than nails. Self-driving into material.
Bolt + nut: Passes through material; nut secures on the other side.
Washer: Flat disc under bolt head or nut; distributes clamping force, protects surface.
Lock washer: Spring or serrated washer resisting loosening from vibration.
Rivet: Permanent fastener — deformed after installation to lock it. A bucking bar backs up the rivet while the head is formed.