Lumos Solem is the incantation of a spell that produces a beam of light. It is possible that the quality of the light is on the warmer solar end of the spectrum; considering the known uses that the spell has been put to, it is not that much of a stretch to presume that the spell is used to conjure sunlight.
Derived from two words; the Latin lumen, meaning "light," and the Latin solis, meaning "of the sun."
Behind the scenes
- Hermione Granger uses this spell to free Ron Weasley from the Devil's Snare in the film adaptation of Harry Potter and the Philosopher's Stone. This was not used in the book, in which she instead frees Harry and Ron with bluebell flames.
- In LEGO Harry Potter: Years 1-4, this spell, as well as its use against Devil's Snare, is taught in a first year Herbology class. This cannot be considered canon, however, as the book states that Professor Sprout only mentioned Devil's Snare in class, not directly covered it.