Fortelet, or Field-Fort, a sconce or little fort, whose flanked angles are generally 120 feet distant from one another. See Fort.

The extent and figure of forts are different, according to the situation and nature of the ground; some of them having whole bastions, and others demi-bastions. They are made use of only for a time, either to defend the lines of circumvallation, or to guard some passage or dangerous post.