The mast of a sailing vessel is a tall spar, or arrangement of spars, erected vertically or near-vertically on the median line of a ship or boat. A mast may carry sails, spars, and derricks. It may also give necessary height to a navigation light, look-out position, signal yard, control position, radio aerial, or signal lamp. Large ships have several masts, with the size and configuration depending on the style of ship. Nearly all sailing masts are guyed.
Until the mid-19th century, all vessels' masts were made of wood, formed from one or several pieces of timber. This was typically the trunk of a single conifer tree; however, from the 16th century, vessels were often built too large for that. Larger vessels needed taller and thicker masts, which could not be made from single tree trunks. To achieve the required height, these masts were built from up to four sections (also called masts). From lowest to highest, these were called "lower", "top", "topgallant", and "royal" masts. For the lower sections to be thick enough, they needed to be built up from multiple pieces of wood. Such a section was known as a made mast, while a section formed from a single piece of timber was known as a pole mast.
