rotunda Meaning, Definition & Usage

  1. noun a building having a circular plan and a dome
  2. noun a large circular room

WordNet

Ro*tun"da noun
Etymology
Cf. It. rotonda, F. rotonde; both fr. L. rotundus round. See Rotund, a.
Definitions
  1. (Arch.) A round building; especially, one that is round both on the outside and inside, like the Pantheon at Rome. Less properly, but very commonly, used for a large round room; as, the rotunda of the Capitol at Washington.

Webster 1913