1. A building or complex of buildings in which a state legislature meets.
2. Capitol The building in Washington, D.C., where the Congress of the United States meets. See Usage Note at capital¹.

[Middle English Capitol, Jupiter's temple in Rome, from Old French capitole, from Latin Capitōlium, after Capitōlīnus, Capitoline, the hill on which Jupiter's temple stoodperhaps akin to caput, capit-, head. See capital¹.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.