A lantern, or lanthorn, is an enclosed source of light. The mundane heraldic lantern (which does not date to period) is a ship’s lantern, spherical and with swivels to keep the inner lamp upright [Bromley & Child 241]. The Society’s default lantern might be more fully termed a “hanging lantern”: an enclosed cylinder or box, often with a handle, containing a candle, which it protects from the elements. If the candle is visible, it’s usually shown lit, whether blazoned so or not.
In early Society heraldry, the lantern was drawn in the form used at the camping events of that time: with large glass panes mounted in a thin frame. This modern form of lantern is no longer registerable, pending period documentation. The more period lantern used panes of horn or oiled parchment; the illustration is taken from a mural painting of the Chapel Notre-Dame des Fontaine, La Brigue, late 15th C. The lantern’s panes may sometimes be explicitly tinctured in the blazon, though no difference is granted for it.
Arthur of Lockhaven bears: Azure, a lanthorn Or.
Thomas Ouswood bears: Vert, a lantern argent enflamed Or.
Saher Faux bears: Or, a staff bendwise, dependent from its dexter end a lantern, all within a bordure indented sable.