An Etymological Dictionary of Astronomy and Astrophysics

1. An act of overcoming or penetrating an obstacle or restriction.
   

   2. A military offensive that penetrates an enemy’s lines of defense.
      

   3. A major achievement or success that permits further progress, as in technology (TheFreeDictionary.com).

Etymology (EN): → break; → through.

Etymology (PE): Tarâšekâft, from tarâ-, → trans-,

• šekâft, past stem of šekâftan “to split, break, tear,” → fission.