12. (Mil.)
Defn: A place or tract of country, protected by fortifications, or by natural advantages, from which the operations of an army proceed, forward movements are made, supplies are furnished, etc.
13. (Mil.)
Defn: The smallest kind of cannon. [Obs.]
14. (Zoöl.)
Defn: That part of an organ by which it is attached to another more central organ.
15. (Crystallog.)
Defn: The basal plane of a crystal.
16. (Geol.)
Defn: The ground mass of a rock, especially if not distinctly crystalline.