Both Uses of
keystone
in
The Return of the King
- At last they came out of shadow to the seventh gate, and the warm sun that shone down beyond the river, as Frodo walked in the glades of Ithilien, glowed here on the smooth walls and rooted pillars, and the great arch with keystone carven in the likeness of a crowned and kingly head.†
Chpt 5.1
- The keystone of the arch crashed almost on their heels, and the wall above crumbled, and fell in ruin.†
Chpt 6.1 *
Definition:
the most important part of something, on which everything else depends
or:
the central stone at the top of an arch that holds the structure together
or:
the central stone at the top of an arch that holds the structure together