1314, "small freshwater duck," probably from an unrecorded O.E. word cognate with M.Du. teling "teal," M.L.G. telink, from W.Gmc. *taili. As the name of a shade of dark greenish-blue like the color patterns on the fowl's head and wings, it is attested from 1923.
[teel] 
) teal for 1.