A close-fitting garment often worn while surfing or during other water sports under a wetsuit to prevent chafing and provide UV protection and in some cases extra warmth.

(historical) A metal plate used as armour for the knee. / Part of a parapet lying between the gun platform and the bottom of an embrasure.

(software) Initialism of Graphical Modeling Framework.

(set theory, order theory) A total order of some set such that every nonempty subset contains a least element.