a mathematical group whose elements are permutations and in which the product of two permutations is the same permutation as is obtained by performing them in succession.
[pur-kee] /ˈpɜr ki/ adjective, perkier, perkiest. 1. jaunty; cheerful; brisk; pert. /ˈpɜːkɪ/ adjective perkier, perkiest 1. jaunty; lively 2. confident; spirited adj. 1820, from perk (v.) + -y (2). Of young women’s breasts since at least 1937. Related: Perkily; perkiness. adjective Energetic and jaunty; lively; chipper (1855+)
- Pernicious anaemia
noun 1. a form of anaemia characterized by lesions of the spinal cord, weakness, sore tongue, numbness in the arms and legs, diarrhoea, etc: associated with inadequate absorption of vitamin B12
[per-nish-uh s] /pərˈnɪʃ əs/ adjective 1. causing insidious harm or ruin; ruinous; injurious; hurtful: pernicious teachings; a pernicious lie. 2. deadly; fatal: a pernicious disease. 3. Obsolete. evil; wicked. /pəˈnɪʃəs/ adjective 1. wicked or malicious: pernicious lies 2. causing grave harm; deadly adj. early 15c., from Middle French pernicios (13c., Modern French pernicieux) and directly […]
noun, Pathology. 1. a severe anemia caused by the diminution or absence of stomach acid secretion, with consequent failure of the gastric mucosa to secrete the intrinsic factor necessary for the absorption of vitamin B 1 2 , characterized by a great reduction in the number of red blood cells and an increase in their […]