Which word refers to a 'sundial' in Latin?

The correct answer is "solarium," which is a term used in Latin to refer specifically to a sundial. The term comes from the root word "sol," meaning "sun," indicating its primary function to measure time using the position of the sun’s shadow cast upon it.

The other options relate to timekeeping or sundial concepts but are not correct for this context. "Horologium," while it does refer to a timekeeping device, is a broader term for clocks or watches rather than specifically signifying a sundial. "Tempus," meaning "time," refers to the concept of time itself rather than a physical device associated with measuring time. Therefore, "solarium" is the most accurate terminology for the sundial, reflecting its unique purpose and connection to sunlight.