A pen that dispenses ink (usually in paste form) over a hard ball at its point, i.e., over a "ball point".

Key characteristics of a ballpoint pen include:
Ink Type: Uses high-viscosity, oil-based ink that dries fast and prevents smudging.
Mechanism: A small ball bearing at the tip spins to pick up ink from a reservoir and deposit it onto the writing surface.
Tip Structure: The ball is held by a socket, partially exposed to rotate, and partially in contact with the ink supply.
Types: Comes in disposable, inexpensive plastic forms or refillable, higher-quality designs.
Design: Often features a clickable or twist-action mechanism to protect the tip.