Thank you all for your valuable input! :-))
There's only 1 early marriage document that has the surname spelled out "Thomashy".
I'm aware of the strong possibility that the surname (when the family) arrived in America had to have been changed (as many others had) based upon the phonetic sound. I just have a challenge in figuring out what it could have been, but only a few possibilities.
This prompted me to ask here..
-- V/R, Brian D. Kerr, Esq SSG, U.S. Army (Retired) SSA, Brigade G1, U.S. Army (Retired)