Do you know ghouls from goblins and ghosts?
"be peevish or worried," early 12c., from Old English fretan "eat, devour" (in Old English used of monsters and Vikings; in Middle English used of animals' eating), from Proto-Germanic compound *fra- "for-" + *etan "to eat" (cf. Dutch vreton, Old High German freggan, German fressen, Gothic fraitan). Transitive sense of "eat away" is from late 12c. Figurative sense of "irritate, worry, eat one's heart out" is c.1200. Modern German still distinguishes essen for humans and fressen for animals. Related: Fretted; fretting. As a noun, from early 15c.
"ornamental interlaced pattern," late 14c., from Old French frete "interlaced work, trellis work," probably from Frankish *fetur or another Germanic source (cf. Old English fetor, Old High German feggara "fetter") perhaps from notion of "decorative anklet," or of materials "bound" together. The other noun, "ridge on the fingerboard of a guitar," is c.1500 of unknown origin but possibly another sense of Old French frete.
in decorative art and architecture, any one of several types of running or repeated ornament, consisting of lengths of straight lines or narrow bands, usually connected and at right angles to each other in T, L, or square-cornered G shapes, so arranged that the spaces between the lines or bands are approximately equal to the width of the bands. Occasionally the system is arranged so that the lines intersect or interlace, as in the common swastika fret. Because the fret is one of the simplest and most natural of decorative forms, it is one of the most widely spread, found from early times in most art forms and on all continents. Thus, it was a favourite decoration, during and after the 4th dynasty, for the ceilings of tombs in Egypt, where in later examples it was combined with rosettes, scarabs, and the lotus into patterns of great richness.