Definitions for "Blockhouse"
An edifice or structure of heavy timbers or logs for military defense, having its sides loopholed for musketry, and often an upper story projecting over the lower, or so placed upon it as to have its sides make an angle wit the sides of the lower story, thus enabling the defenders to fire downward, and in all directions; -- formerly much used in America and Germany.
A house of squared logs.
A thick-walled concrete bunker to protect personnel from explosions. Usually houses the electronics for a missile launch.
Strong construction used to house personnel and instruments in a static or flight test. Generally has extremely durable overhead construction.
Keywords:  castle, shoot, four, small, openings
a small castle that has four openings through which to shoot