1Having a tail like that of a rat; (in early use especially of a horse) having a rat-tail.
2Designating the aquatic larva of the drone fly (Eristalis tenax), which has a tail-like telescopic breathing tube that enables it to breathe air while submerged. Usually in "rat-tailed maggot", "rat-tailed larva".
3Especially of a spoon: having a tail-like prolongation of the handle along the back of the bowl; that has a rat-tail.
4Of a comb: that has a long, tapering handle at one end.
Late 17th century; earliest use found in The London Gazette. From rat + tailed.