light in a transparent protective case
"The fisherman carried an old glass lantern to guide his boat through the foggy harbor."
A case of translucent or transparent material made to protect a flame, or light, used to illuminate its surroundings.
"The sailor hung his oil lantern on the railing to guide ships safely into the harbor during the stormy night."
In plain English: A lantern is a portable light that usually has glass sides and hangs from your hand to help you see when it's dark outside.
"The hikers carried an old lantern to light their way through the dark forest."
Usage: The word "lantern" refers specifically to an enclosed light source; use the verb "illuminate" if you simply mean to make something bright without implying a physical container. Avoid confusing it with "lamp," which typically denotes a fixed or portable fixture that does not necessarily enclose the flame in a protective case.
To furnish with a lantern.
"The old sailor decided to lantern his cabin before heading out on the night watch."
In plain English: To lantern something means to shine a light on it so people can see what is happening there.
"The campers decided to lantern their way through the dark forest at night."
The word lantern comes from Latin lanterna, which was originally borrowed from Ancient Greek for "torch" but changed in meaning under the influence of the Latin word for lamp. In English, the spelling once shifted to "lanthorn" because people mistakenly associated it with the horn material used as a cover.