Hortsense Glossary FullABCDEFGHIJKLMNOPQRSTUVWXYZ TermDefinition oedemaa blister formation due to an increase in intercellular water in leaves. oppositetwo at a node, as leaves. overwinterssurvives the winter in a protected place in a state of physiological "shut-down". oxalate/oxalic acida very strong acid. (COOH)2