manuka honey n honey from the nectar of the manuka tree, often used for medicinal purposes; known as active manuka honey if it has a UMF rating of over 10. Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014