1. From that place or from there
   "proceeded thence directly to college"; "flew to Helsinki and thence to Moscow";
   - therefrom
    
2. From that circumstance or source
   "atomic formulas and all compounds thence constructible"; "a natural conclusion follows thence";
   - therefrom, thereof
    
3. (used to introduce a logical conclusion) from that fact, reason or as a result
   "we were young and thence optimistic";
   - therefore, hence, thus, so

Encyclopedia: Thence