from
The Collaborative International Dictionary of English v.0.48
Four-o'clock \Four"-o'clock`\, n.
1. (Bot.) A plant of the genus {Mirabilis}. There are about
half a dozen species, natives of the warmer parts of
America. The common four-o'clock is {M. Jalapa}. Its
flowers are white, yellow, and red, and open toward
sunset, or earlier in cloudy weather; hence the name. It
is also called {marvel of Peru}, and {afternoon lady}.
[1913 Webster]
2. (Zool.) The friar bird; -- so called from its cry, which
resembles these words.
[1913 Webster]