in·fu·sion (?n-fyo?o?zh?n)n.1. The act or process of infusing.2. Something infused or introduced: an economy in need of regular capital infusions.3. The liquid product obtained by infusing: prepared an infusion of medicinal herbs.4. a. Introduction of a solution into the body through a vein for therapeutic purposes.b. The solution so introduced: a sucrose infusion.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.infusion (?n?fju???n) n1. the act of infusing2. something infused3. an extract obtained by soaking4. (Medicine) med introduction of a liquid, such as a saline solution, into a vein or the subcutaneous tissues of the body infusive adjCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014in?fu?sion (?n?fyu ??n) n. 1. the act or process of infusing. 2. something that is infused. 3. a liquid extract, as tea, prepared by steeping or soaking. 4. a. the introduction of a saline or other solution into a vein. b. the solution used. [1400?50; late Middle English