Definition of "light beam" []

• A column of light (as from a beacon) (noun)

WordNet. Princeton University. 2010.

• "Einstein loved gedanken experiments; his most famous was imagining as a boy that he was riding alongside a light beam traveling at the speed of light."
• "She had augmented the light beam with enough visible-frequency rays to allow the user to see where the beam was being directed."
• "It was possible for a light beam to cut at least partially through the sludge and drifting guck and pervasive brownness of the water to show the slimy gravel and rusty track over which they were passing, the furry tree stumps on both sides."