Turret (architecture) in the context of "Castle Geyser"

A watchtower or guardtower (also spelt watch tower, guard tower) is a type of military/paramilitary or policiary tower used for guarding an area. Sometimes fortified, and armed with heavy weaponry, especially historically, the structures are built in areas of established control. These include military bases, cities occupied by military forces, prisons and more. A common equipment is searchlights.

It differs from a regular tower in that its primary use is military/policiary and from a turret in that it is usually a freestanding structure. Its main purpose is to provide a high, safe place from which a sentinel or guard may observe the surrounding area. In some cases, non-military towers, such as religious towers, may also be used as watchtowers.

A bartizan (an alteration of bratticing), also called a guerite, garita, or échauguette, or spelled bartisan, is an overhanging turret projecting from the walls of late-medieval and early-modern fortifications from the early 14th century up to the 18th century. Most frequently found at corners, they protected a warder and enabled him to see his surroundings. Bartizans are generally furnished with oillets or arrow slits. The turret was usually supported by stepped masonry corbels and could be round, polygonal or square.

Bartizans were incorporated into many notable examples of Scottish Baronial architecture. In the architecture of Aberdeen, the new Town House, built in 1868–74, incorporates bartizans in the West Tower.

A belvedere (/ˈbɛlvəˌdɪər/ BEL-və-deer; Italian for 'beautiful view') or belvidere is an architectural structure sited to take advantage of a fine or scenic view. The term has been used both for rooms in the upper part of a building or structures on the roof, or a separate pavilion in a garden or park. The actual structure can be of any form or style, including a turret, a cupola or an open gallery. The term may be also used for a paved terrace or just a place with a good viewpoint, but no actual building.

It has also been used as a name for a whole building, as in the Belvedere, Vienna, a huge palace, or Belvedere Castle, a folly in Central Park in New York.

A tourelle is a type of turret, sometimes used in Chateauesque architecture.

A general dictionary defines tourelle as "a small tower (as one springing from corbeling or pier)".

A pinnacle is an architectural element originally forming the cap or crown of a buttress or small turret, but afterwards used on parapets at the corners of towers and in many other situations. The pinnacle looks like a small spire. It was mainly used in Gothic architecture.