Definition of "hummingbird"

Soon I hear the low all-pervading hum of an approaching hummingbird circling above the rock, [...]

1857 Thoreau, Henry David, journal entry, May 29, 1857. From Thoreau on Birds: notes on New England birds from the Journals of Henry David Thoreau, Boston: Beacon Press, 1993, p238. (Originally published as the anthology Thoreau's bird-lore, Boston: Houghton Mifflin, 1910, edited by Francis H. Allen.)

Beyond the veranda was a small cleared garden, bounded with cactus hedges and adorned with clumps of flowering shrubs, round which the great blue butterflies and the tiny humming-birds fluttered and darted in crescents of sparkling light.

1912, Arthur Conan Doyle, The Lost World […], London, New York, N.Y.: Hodder and Stoughton