mar·i·jua·na also mar·i·hua·na (m?r??-wä?n?)n.1. The cannabis plant.2. The dried flower clusters and leaves of this plant, smoked or ingested to induce euphoria or to treat the symptoms of certain medical conditions. Use of marijuana is illegal under federal law, but certain jurisdictions permit regulated use for medical or recreational purposes.[Spanish marihuana.]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.marijuana (?mær??hw??n?) or marihuanan1. (Recreational Drugs) the dried leaves and flowers of the hemp plant, used for its euphoric effects, esp in the form of cigarettes. See also cannabis2. (Plants) another name for hemp1[C19: from Mexican Spanish]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ma?ri?jua?na or ma?ri?hua?na (?mær ??w? n?) n. 1. the dried leaves and female flowers of the hemp plant used esp. in cigarette form as an intoxicant. 2. hemp (def. 1). [1890?95, Amer.;