Columbiad \Co*lum"bi*ad\, n. [From Columbia the United States.]
(Mil.)
A form of seacoast cannon; a long, chambered gun designed for
throwing shot or shells with heavy charges of powder, at high
angles of elevation.
[1913 Webster]
Note: Since the War of 1812 the Columbiad has been much
modified, especially by General Rodman, and the
improved form now used in seacoast defense is often
called the {Rodman gun}.
[1913 Webster]