platelet
(ˈpleɪtlɪt)
[See -let.]
1. A small or minute plate. blood-platelet, a minute colourless disk-shaped corpuscle which exists in large numbers in the blood of all mammalia; usu. simply platelet [(blood-)platelet tr. G. (blut)plättchen (G. Bizzozero in Centralbl. für die med. Wissensch. (1882) I. 17, 18), F. petite plaque (du sang) (idem in Arch. ital. de Biol. (1882) I. 1, 16)].
| 1895 Syd. Soc. Lex., Platelets, blood-, the same as blood⁓plates. 1895 in Daily News 13 Aug. 6/1 The armour of these strange animals consisted of either circular or many-sided plates, encircled by a rim of smaller polygonal platelets. 1898 Allbutt's Syst. Med. V. 400 A minute spindle-shaped body, the hæmatoblast, not unlike a blood platelet. 1910 H. W. Armit tr. P. Ehrlich's Anæmia iv. 203 He then determined the relative proportions of the platelets to the blood corpuscles. 1955 Sci. News Let. 14 May 320/3 Platelets, tiny cell fragments found in the blood, arrest bleeding by sticking to the edge of the wound and to each other until they pile up into a little cork that fills the hole. 1970 Physics Bull. July 322/1 The crystal..is then sliced into platelets 50 µm or so thick. 1978 Detroit Free Press 5 Mar. b4/1 Blood clots that block arteries are formed by platelets, the body's first line of defense against injury. |
2. platelet count, the number of platelets in a stated volume of blood; a calculation of this.
| 1909 Jrnl. Exper. Med. XI. 542 In the experiments careful erythrocyte and leukocyte counts have been made and then the platelet count obtained by the indirect method, i.e., by ascertaining their number relative to that of the red blood cells in fresh preparations and checking this result by the relative number in carefully made stained smears. Ibid. 544 In an animal which had received repeated doses of saponin intravenously..there was a high platelet count (1,400,000 per cubic millimeter). 1966 Lancet 24 Dec. 1384/1 The platelet-count gradually recovered after the drugs had been stopped. |