naumachia

noun, plural nau·ma·chi·ae [naw-mey-kee-ee] /nɔˈmeɪ kiˌi/, nau·ma·chi·as.

1. a mock sea fight, given as a spectacle among the ancient Romans.
2. a place for presenting such spectacles.

noun plural -chiae (-kɪˌiː), -chias or -chies (in ancient Rome)

1. a mock sea fight performed as an entertainment
2. an artificial lake used in such a spectacle