Our ‘A’ to ‘Z’ of Gardening Terms

Terms that begin with “O”

organic fertilizerA natural fertilizer material that has undergone little or no processing. Can include plant, animal, or mineral materials.
organic matterAny material originating from a living organism (peat moss, plant residue, compost, ground bark, manure, etc.).
organismA living plant or animal.
ornamental plantA plant grown for beautification, screening, accent, specimen, color, or other aesthetic reasons.
orthopteraAn insect family made up of species having a tough, leathery shell, membranous hindwings, and straight forewings. Includes locusts, crickets, grasshoppers, and katydids.
osmosisPassage of materials through a membrane from an area of high concentration to an area of lower concentration.
ovaryThe part of a flower containing ovules that will develop into seeds upon fertilization. Along with the style and stigma, it makes up the pistil (female sexual organ).
ovuleWithin the ovary, a body that will develop into seeds after fertilization.
oxidationThe chemical process by which sugars and starches are converted into energy. In plants, this is also known as respiration.