means The act or result of covering a surface with shapes—often repeating—so they fit together without gaps or overlaps, whether on a floor, wall, or computer screen.

from From 'tile,' which comes from Old English 'tigele,' itself borrowed from Latin 'tegula'—a tile—rooted in the verb 'tegere,' 'to cover' (a cousin of words like 'protect' and 'detect,' all about covering or uncovering). The '-ing' is the plain English suffix turning the act into a noun, so 'tiling' is literally 'the covering-with-tiles.' Mathematicians later borrowed the word for any gap-free covering of the plane, keeping faith with that ancient Latin idea of laying things down to cover a surface.