What is a yardarms on a ship?

Yardarms are horizontal spars that extend from a ship's mast, typically used to support sails. Each mast can have multiple yardarms, which help to control the shape and position of the sails to optimize wind capture. The term is often associated with traditional sailing ships, where yardarms play a critical role in sail management and maneuverability. They are also used as reference points for various nautical measurements and signaling.