Also 7 bulbe. [ad. Lat. bulb-us a. Gr. βολβός onion, bulbous root.]
† 1. An onion. Obs.
1568. Turner, Herbal, II. 62. The roote wtin is whyte rounde and knoppy after the lyknes of a bulb.
1578. Lyte, Dodoens, V. lxxvii. 644. Lyke an Onyon or Bulbe.
1601. Holland, Pliny, II. 329. Asses milke warme, or sodden together with bulbe roots.
a. 1712. King, Orpheus & E. (Misc.), 394. Iesuit Bulbs ty’d up with Ropes.
2. Bot. The underground spheroidal portion of the stem of an onion, lily, or other plant of analogous mode of growth; formerly, and still in popular language, regarded as a kind of ‘root,’ but by modern botanists defined either as ‘a subterranean bud … sending off roots from below and a stem above,’ or as ‘a very short stem, producing roots below, and leaves in the form of scales above.’ Sometimes popularly applied to a solid tuber of similar external shape.
1664. Evelyn, Sylva (1679), Advt., Bulbs, round or onion-shap’d roots.
1712. trans. Pomet’s Hist. Drugs, I. 100. Chuse such Roots or Bulbs, as are sound.
1794. Martyn, Rousseau’s Bot., i. 24. The roots are bulbs of some sort or other.
1858. Carpenter, Veg. Phys., § 119. Bulbs … are in reality underground stems in the state of buds.
1884. Bower & Scott, De Bary’s Phaner. & Ferns, 142. There lies … on the outer side of the … scales of the bulb, one prismatic crystal.
b. An axillary leaf-bud of bulbous form which detaches itself from the stem, becoming an independent plant, a bulbil.
1845. Lindley, Sch. Bot., x. (1858), 162. When they [leaf-buds] disarticulate from the stem … they are called bulbs.
1862. Huxley, Lect. Wrkg. Men, 84. A little bulb or portion of the plant drops off, detaches itself and becomes capable of growing as a separate thing.
3. transf. Anat. A roundish dilatation of any cylindrical organ or structure in an animal body, e.g., central bulb, ‘the bulbous extremity of a nerve-fibril in a corpuscle of Krause’; olfactory bulb, the anterior oval termination of the olfactory tract; auditory bulb, the membranous labyrinth and the cochlea together; bulb of the hair, the soft enlargement of the root end of the hair; bulb of spinal marrow, the medulla oblongata.
1715. Phil. Trans., XXIX. 327. The Bulb of the Pulmonary Vein … was extraordinarily dilated.
1758. J. S., Le Dran’s Observ. Surg. (1771), 261. The End of the Bulb of the Urethra.
1813. J. Thomson, Lect. Inflam., 614. The small bulbs which surround the roots of the hair.
1870. Rolleston, Anim. Life, Introd. 46. The olfactory bulbs are absent.
4. A bulb-like dilatation of a glass tube. Also (rarely) a lump of metal of bulbous shape.
1800. Vince, Hydrostat., x. (1806), 95. A glass tube with a bulb at the bottom.
1831. Brewster, Optics, x. 89. The bulb of the thermometer.
1833. J. Holland, Manuf. Metals, II. 302. The metal bulb, which is moved along the graduated line of the lever, to ascertain the weight.
1856. Enquire Within on Ev. (1862), 278. Glass water bulbs that are sold by men in the Loudon streets at one penny each.
1884. Daily News, 3 Sept., 3/1. The bower is illuminated by two Edison incandescent electric light bulbs.
5. Comb., as bulb-like adj.; also bulb-iron, angle-iron (Mech.), a bulbed iron or angle-iron used to strengthen joints or angles in the framework of ships; bulb-scales (see quot.); bulb-tube, a tube terminating in a bulb.
1869. Sir E. Reed, Shipbuild., i. 10. To introduce separate straps for the *bulb-irons. Ibid., viii. 138. A bulb angle-iron has been used for the deck beam.
1836–9. Todd, Cycl. Anat. & Phys., II. 962/1. A soft *bulb-like extremity.
1882. Vines, Sachs’ Bot., 714. The *bulb-scales of the Tulip.
1839–47. Todd, Cycl. Anat. & Phys., III. 818/2. The contents of the *bulb-tube are emptied into a small evaporating dish.
