Miscellaneous Symbols is a Unicode block (U+2600âU+26FF) containing glyphs representing concepts from a variety of categories, astrological, astronomical, chess, dice, musical notation, political symbols, recycling, religious symbols, trigrams, warning signs, and weather, among others.iscellaneous Symbols is a Unicode block (U+2600âU+26FF) containing glyphs representing concepts from a variety of categories, astrological, astronomical, chess, dice, musical notation, political symbols, recycling, religious symbols, trigrams, warning signs, and weather, among others.
reactant. 1  a person or thing that reacts. 2  Also called interactant. Chemistry. any substance that undergoes a chemical change in a given reaction.
Post. Share. Reactant Definition: Starting material in a chemical reaction. Examples: H 2 and O 2 are reactants in the reaction H 2 (g) + 1/2 O 2 (g) â H 2 O(l). Return to the Chemistry Glossary Index. By Anne Marie Helmenstine, Ph.D.