What's the difference between i.e. and e.g.?
"beam of light," c.1300, from Old French rai (nominative rais) "ray (of the sun), spoke (of a wheel); gush, spurt," from Latin radius "ray, spoke, staff, rod" (see radius). Not common before 17c. [OED]; of the sun, usually in reference to heat (beam being preferred for light). Science fiction ray-gun is first recorded 1931 (but cf. Martian Heat ray weapon in H.G. Wells' "War of the Worlds," 1898).
type of fish related to sharks, early 14c., from French raie (13c.), from Latin raia, of unknown origin.
A narrow beam of light or other electromagnetic radiation.
A narrow beam of particles, as a cathode.
A structure or part having the form of a straight line extending from a point.
Ray (rā), John. 1627-1705.
English naturalist who was the first to use anatomy to distinguish between specific plants and animals. He established the species as the basic classification of living things.