The mast of a sailing ship is a tall vertical pole which supports the sails. Larger ships have several masts, with the size depending on the style of ship.

Until the 20th century, a ship's masts would be wooden spars, originally constructed from a single straight tree trunk. As ship sizes increased, taller masts were constructed by lashing up to three spars together.

• http://www.bluewatersailing.com/shipclass.php Archived 2010-09-23 at the Wayback Machine
• http://www.hms-trincomalee.co.uk/virtual/rigging/sails.htm Archived 2006-04-05 at the Wayback Machine
• http://tallships.sailtraining.org/sailrigs.htm Archived 2008-03-05 at the Wayback Machine
• http://boatdesign.net/articles/mast-materials/
• Glossary of Nautical terms, sailing and boat parts Archived 2006-10-25 at the Wayback Machine