The Collaborative International Dictionary of English v.0.48:

Tiny \Ti"ny\, a. [Compar. Tinier; superl. Tiniest.]
   [Probably fr. tine, teen, trouble, distress, vexation.]
   Very small; little; puny.
   [1913 Webster]

         When that I was and a little tiny boy.   --Shak.
   [1913 Webster]