A ravelin is a triangular fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

 or detached outwork

Outwork

An outwork is a minor defense, fortification, built or established outside the principal fortification limits, detached or semidetached. Outworks were developed in the 16th century, such as ravelins, lunettes , caponiers to shield bastions and fortification curtains from direct battery...

, located in front of the innerworks of a fortress (the curtain walls

Curtain wall (fortification)

A curtain wall is a defensive wall between two bastions of a castle or fortress.In earlier designs of castle the curtain walls were often built to a considerable height and were fronted by a ditch or moat to make assault difficult....

 and bastion

Bastion

A bastion, or a bulwark, is a structure projecting outward from the main enclosure of a fortification, situated in both corners of a straight wall , facilitating active defence against assaulting troops...

s). Originally called a demi-lune, after the lunette

Lunette (fortification)

In fortification a lunette was originally an outwork of half-moon shape; later it became a redan with short flanks, in trace somewhat resembling a bastion standing by itself without curtains on either side...

, the ravelin is placed outside a castle and opposite a fortification curtain.

The edges of the ravelin are placed so that the guns there can sweep fire upon the attacking troops as they approach the curtain

Curtain wall (fortification)

A curtain wall is a defensive wall between two bastions of a castle or fortress.In earlier designs of castle the curtain walls were often built to a considerable height and were fronted by a ditch or moat to make assault difficult....

. The wall facing the inner fortifications is low and designed so that it will not provide shelter to attacking forces in case the ravelin is overtaken by the attackers or abandoned by the defenders.

The word appears in the Major-General's Song

Major-General's Song

I Am the Very Model of a Modern Major-General is a patter song from Gilbert and Sullivan's 1879 comic opera The Pirates of Penzance. It is perhaps the most famous song in Gilbert and Sullivan's operas. It is sung by Major-General Stanley at his first entrance, towards the end of Act I...

 from the comic opera

Comic opera

Comic opera denotes a sung dramatic work of a light or comic nature, usually with a happy ending.Forms of comic opera first developed in late 17th-century Italy. By the 1730s, a new operatic genre, opera buffa, emerged as an alternative to opera seria...

 The Pirates of Penzance

The Pirates of Penzance

The Pirates of Penzance; or, The Slave of Duty is a comic opera in two acts, with music by Arthur Sullivan and libretto by W. S. Gilbert. The opera's official premiere was at the Fifth Avenue Theatre in New York City on 31 December 1879, where the show was well received by both audiences...

, by Gilbert & Sullivan, in which General Stanley sings, "In fact, when I know what is meant by mamelon and ravelin..."

See also

• List of established military terms
• Raveleijn (Efteling)