as·pi·rin (?s?p?r-?n, -pr?n) n. pl. aspirin or as·pi·rins 1. A white, crystalline compound, C9H8O4, derived from salicylic acid and commonly used in tablet form to relieve pain and reduce fever and inflammation. It is also used as an antiplatelet agent. Also called acetylsalicylic acid. 2. A tablet of aspirin. [Originally a trademark.] Word History: The English word aspirin comes from the German trademark Aspirin, which is made up of elements from an obsolete German term for acetylsalicylic acid, acetylierte Spirsäure, literally, “acetylated Spiraea-acid.” Acetylsalicylic acid was first isolated in a species of meadowsweet, Filipendula ulmaria, which was formerly classified in the genus Spiraea, the genus that includes many of the garden plants called spirea. American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.aspirin (?æspr?n) n, pl -rin or -rins1. (Pharmacology) a white crystalline compound widely used in the form of tablets to relieve pain and fever, to reduce inflammation, and to prevent strokes. Formula: CH3COOC6H4COOH. Chemical name: acetylsalicylic acid 2. (Pharmacology) a tablet of aspirin[C19: from German, from A(cetyl) + Spir(säure) spiraeic acid (modern salicylic acid) + -in; see also spiraea]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014as?pi?rin (?æs p?r ?n, -pr?n) n., pl. -rin, -rins. 1. a white, crystalline substance, C9H8O4, derivative of salicylic acid, used as an anti-inflammatory agent and to relieve pain and fever; acetylsalicylic acid. 2. a tablet of this. [1899;