The Collaborative International Dictionary of English v.0.48:

Lone-Star State \Lone-Star State\ prop. n.
   Texas; -- a nickname alluding to the single star on its coat
   of arms, being the device used on its flag and seal when it
   was a republic.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Lone-Star State
    n 1: the second largest state; located in southwestern United
         States on the Gulf of Mexico [syn: Texas, Lone-Star
         State, TX]