| 1. | tubercle bacillus. |
| 2. | tuberculosis. |
| terbium. |
[too-bur-kyuh-loh-sis, tyoo-] 
| 1. | an infectious disease that may affect almost any tissue of the body, esp. the lungs, caused by the organism Mycobacterium tuberculosis, and characterized by tubercles. |
| 2. | this disease when affecting the lungs; pulmonary phthisis; consumption. |
| 3. | any disease caused by a mycobacterium. |
| Tb 1 The symbol for the element terbium. |
| Tb 2 abbr. Bible Tobit |
| TB abbr. tuberculosis |
| ter·bi·um (tûr'bē-əm) n. Symbol Tb A soft, silvery-gray metallic rare-earth element, used in x-ray and color television tubes. Atomic number 65; atomic weight 158.925; melting point 1,356°C; boiling point 3,123°C; specific gravity 8.229; valence 3, 4. See Table at element. [After Ytterby, a town in Sweden.] |
| To·bit 2 (tō'bĭt) n. Abbr. Tob. or Tb See Table at Bible. [After Tobit.] |
| tu·ber·cu·lo·sis (tŏŏ-bûr'kyə-lō'sĭs, tyŏŏ-) n. Abbr. TB
[Latin tūberculum, tubercle; see tubercle + -osis.] |
An infectious disease caused by bacteria that mainly attack the lungs. The disease is characterized by the formation of patches, called tubercles, that appear in the lungs and, in later stages, the bones, joints, and other parts of the body. Tuberculosis is treated with combinations of antibiotics and is no longer considered a major health problem in industrialized countries. It was formerly called consumption.
Note: Years ago, tuberculosis (consumption) was a major killer; it often figures in literature and drama.
Note: In recent years, the incidence of tuberculosis has been on the increase in the United States, particularly in large cities, mainly because the strains of the bacterium have developed resistance to antibiotics.
Tb 1
The symbol for the element terbium.
TB or T.B.
abbr.
tuberculosis
tuberculosis tu·ber·cu·lo·sis (t&oobreve;-bûr'kyə-lō'sĭs, ty&oobreve;-)
n.
Abbr. TB, T.B.
An infectious disease of humans and animals caused by the tubercle bacillus and characterized by the formation of tubercles on the lungs and other tissues of the body, often developing long after the initial infection.
Tuberculosis of the lungs, characterized by the coughing up of mucus and sputum, fever, weight loss, and chest pain.
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Tb
(Tb), chemical element, rare-earth metal of the lanthanoid series of the periodic table. One of the least abundant of the rare earths, terbium, when reduced to metallic form, is silvery white and is slowly oxidized by air at room temperatures and by cold water. The element was discovered in 1843 by Carl Gustaf Mosander in a heavy rare-earth fraction called yttria, but its existence was not confirmed for at least 30 years, and pure compounds were not prepared until 1905. Terbium occurs in many rare-earth minerals but is almost exclusively obtained as a by-product from monazite sands, which are a source of thorium. It is also found in the products of nuclear fission. Ion-exchange techniques are utilized for its commercial production. The metal is prepared in a highly pure form by thermoreduction of the anhydrous fluoride with calcium metal. At room temperature the atoms of the pure element adopt the hexagonal close-packed structure. The only isotope occurring in ores is terbium-159. About 20 radioactive artificial isotopes have been prepared, such as terbium-160 (73-day half-life). Sodium terbium borate as a laser material emits coherent light at 5,460 angstroms. In certain solid-state devices terbium is used to dope calcium fluoride, calcium tungstate, and strontium molybdate.
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kyəˈloʊ
