Other forms: gests
A gest is something you would read about in a tale of King Arthur, such as a heroic deed or exploit by one of Arthur's knights. Geste is another spelling of the word.
A gest may also be a poem or story about an epic deed or exploit. For example, The Song of Roland is an 11th-century French poem or gest about the heroic deeds of the emperor Charlemagne's knights. In fact, the French word geste is where we got our word gest in the medieval period, since French literature was the main source of such stories and poems. The Song of Roland belongs to a category of poem called chanson de geste in French, "song of heroic deeds."