eucalyptus

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of numerous tall trees of the genus Eucalyptus, native to Australia and having aromatic leaves that yield an oil used medicinally and wood valued as timber.

Century Dictionary and Cyclopedia

1. n. An important genus of myrtaceous evergreen trees and shrubs, including about 120 species, abundant in all parts of Australia, and occurring rarely in New Guinea, Timor, and the Moluccas. The flowers are usually in axillary umbels, with a firm, deciduous, calyptra-like calyx, no petals, and very numerous stamens. The seeds are very small. The leaves are thick and smooth, mostly similar on both sides, and thrown into a vertical position by a twist of the petiole, glandular - punctate, and with a strong, peculiar odor. The matured wood is always hard, and the timber is often very valuable. Many of the arboreous species are very tall; and some, as E. amygdalina and E. diversicolor, reach a height of over 400 feet, exceeding in this respect all other known trees. Many species exude a gum (a kind of kino), whence the common name of gum-tree. From the extreme hardness or the fibrous character of the bark, some are known as iron-bark or stringy-bark trees, and others are distinguished as mountain-ash, box-, or mahogany-trees, etc. E. sideroploia, which is the principal iron bark-tree, and E. resinifera, are the chief source of Botany Bay kino. The leaves of various species, especially of E. globulus, and the oil extracted from them, are said to have important remedial powers in asthma, bronchitis, and various other diseases. The trees are of very rapid growth, and several species, especially the blue-gum, E. globulus, have been extensively planted in warm countries for their timber. Their culture in malarious districts has also been recommended for the purpose of counteracting miasmatic influences.

Wiktionary

1. n. Any of many trees, of genus Eucalyptus, native mainly to Australia.

GNU Webster's 1913

1. n. (Bot.) A myrtaceous genus of trees, mostly Australian. Many of them grow to an immense height, one or two species exceeding the height even of the California Sequoia.

WordNet 3.0

1. n. a tree of the genus Eucalyptus
2. n. wood of any of various eucalyptus trees valued as timber