-teen Look up -teen at Dictionary.com
combining form meaning "ten more than," from O.E. -tene, -tiene, from P.Gmc. *tekhuniz (cf. O.S. -tein, Du. -tien, O.H.G. -zehan, Ger. -zehn, Goth. -taihun), an inflected form of the root of ten; cognate with L. -decim (cf. It. -dici, Sp. -ce, Fr. -ze). The combining form of ordinal numbers, -teenth, developed from O.E. -teoša, -teoše (W.Saxon), teogoša (Anglian) "tenth."