1610s, "issue or spread in all directions from a point in rays or straight lines," from Latin radiatus, past participle of radiare "to beam, shine, gleam; make beaming," from radius "beam of light; spoke of a wheel" (see radius). Meaning "be radiant, give off rays (of light or heat)" is from 1640s. Related: Radiated; radiates; radiating.
"having rays, furnished with rays or ray-like parts, shining," 1660s, from Latin radiatus, past participle of radiare "to beam, shine, gleam; make beaming," from radius "beam of light; spoke of a wheel" (see radius).
1832, "any thing which radiates," agent noun in Latin form from radiate (v.). Originally a stove-like apparatus, as a device designed to communicate heat from steam to a room by 1855; the sense of "cooling device in an internal combustion engine" is by 1899.
mid-14c., nouel, nowel, "pillar from which steps of a winding stair radiate, stone cut to form a step and a section of the central pillar of a spiral stair," from Old French noel, noiel, novel "knob, newel, kernel, stone" (Modern French noyau), from Vulgar Latin *nodellus "little knot," diminutive of Latin nodulus, itself a diminutive of nodus "knot" (from PIE root *ned- "to bind, tie").
Klein's sources suggest the French word may be from Gallo-Roman *nucale, from Latin nux "nut." The carpentry meaning "tall and more or less ornamental post at the top or bottom of a staircase" is from 1833 (newel-post in this sense is from 1798).