verb

• (transitive, obsolete or poetic) Especially when describing animals: to consume, devour, or eat.
  "At the beginning God gaue the dome him ſelfe / That Adam and Eue and all them that ſewed, / Shuld dye down right and dwell in pyne after, / If that they touched a tree and the frute eaten, / Adam afterwarde agaynſt hys defence / freet of that frute, and forſake as it were, / The loue of our lord and his lore bothe, [...]"
• (transitive) To chafe or irritate; to worry.
  "A Perſon of Honour, of a full Body abounding with ſharp Humours, was ſeized with an Herpes on his right Leg. [...] [I]t inflamed and ſwelled very much, many Wheals aroſe, and fretted one into another, with great Excoriation."
• (transitive) To make rough, to agitate or disturb; to cause to ripple.
  "to fret the surface of water"
• (transitive) In the form fret out: to squander, to waste.
  "Yorke hereupon conſults with his ſpeciall friends; [...] how Yorke might get the Crowne of England, and for that cauſe how to ruine or fret out the Duke of Sommerſet; who ſtanding, they were to looke for ſtrong oppoſition."

noun

• (mining, in the plural) The worn sides of riverbanks, where ores or stones containing them accumulate after being washed down from higher ground, which thus indicate to miners the locality of veins of ore.
  "Then we obſerve the Frets in the Banks of Rivers that are newly made by any great Land-Flood, which uſually are then very clean, to ſee, if happily we can diſcover any metalline Stones in the Sides and Bottoms thereof, together with the Caſt of the Country (i.e. any earth of a different colour from the reſt of the Bank), which is a great help to direct us, which ſide or hill to ſearch into."

noun

• (heraldry) A saltire interlaced with a mascle.
  "DIAPERED, or Diapre, in heraldry, the dividing of a field in planes, like fret-work, and filling the ſame with variety of figures. This chiefly obtains on bordures, which are diapered or fretted over, and the frets charged with things proper for bordures."

verb

• (transitive) To decorate or ornament, especially with an interlaced or interwoven pattern, or (architecture) with carving or relief (raised) work.
  "In a long purple pall, whose ſkirt with gold, / Was fretted all about, ſhe was arayd, [...]"
• (transitive) To form a pattern on; to variegate.
  "Decius. Here lyes the Eaſt: doth not the Day breake heere? [...] Cin[na]. O pardon, Sir, it doth; and yon grey Lines, / That fret the Clouds, are Meſſengers of Day."
• (transitive) To cut through with a fretsaw, to create fretwork.