Fillet  —n. 1 a boneless piece of meat or fish. B (in full fillet steak) undercut of a sirloin. 2 ribbon etc. Binding the hair. 3 thin narrow strip or ridge. 4 narrow flat band between mouldings. —v. (-t-) 1 remove bones from (fish or meat) or divide into fillets. 2 bind or provide with fillet(s). [latin filum thread]