In "The Star-Spangled Banner," the synonym for fortified elevation is: Ramparts, Reposes, Host, Ocean, Banner?

In the poem, "The Star-Spangled banner," the synonym for
fortified elevation is ramparts. Look at the usage of the word in the lines given below, "O'er
the ramparts we watched," it is evident that a reference is being made to something that is
elevated and acts as a barrier to protect the viewers from the flying rockets and
bombs.

Whose broad
stripes and bright stars through the perilous fight,
O'er the
ramparts we watched were so gallantly
streaming;
And the rocket's red glare, the bombs bursting in
air,

The definition for a rampart as
given at href="http://dictionary.reference.com/browse/ramparts">http://dictionary.reference.com
is "a broad elevation or mound of earth raised as a fortification around a place and usually
capped with a stone or earth parapet." The other terms: reposes, host, ocean and banner do not
mean a fortified elevation.