The Collaborative International Dictionary of English v.0.48:

Gentoo \Gen*too"\ (j[e^]n*t[=oo]"), n.; pl. Gentoos
   (j[e^]n*t[=oo]z"). [Pg. gentio gentile, heathen. See
   Gentile.]
   A native of Hindostan; a Hindoo. [Archaic]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gentoo \Gen*too"\ (j[e^]n*t[=oo]"), n.; pl. Gentoos
   (j[e^]n*t[=oo]z").
   A penguin (Pygosceles t[ae]niata). [Falkland Is.]
   [Webster 1913 Suppl.]