Distinctness 
Plant Breeders have rights of protection over plant varieties they develop, and a variety must have distinct primary, and where required secondary characteristics, such as ploidy; Intensity of green colour of leaf; Numbers of tiller; and many more.
Division
A taxonomic category that is used to group organisms: It is now more often referred to as a Phylum in botany. They are grouped from a similar Class. Similar Divisions or Phyla are in turn grouped into a Kingdom.
Domain
The highest taxonomic category for a group of organisms in the three-domain system proposed by Carl Woese. The domains are Archaea, Bacteria and Eukarya. It is also referred to as Superkingdom.
Domin Scale
A scale used to estimate the cover and abundance of species within a defined area such as a quadrat, being estimated from a vertical perspective. The National Vegetation Classification use the following values, where for each recorded species an estimate should be made of its quantitative contribution to the vegetation.
Dormancy
A state of inactivity for an entire plant or part of a plant. This can be a useful survival strategy when stressful environmental conditions are present, for example, shortage of available water, extreme heat, very cold conditions, or a shortage of nutrients. The plant is able to conserve what internal resources it has, ideally until the return of more suitable environmental conditions when normal growth and development may then continue.
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Drought
Two types of drought are routinely experienced on turf surfaces: shorter term Agricultural drought, and the longer-term Meteorological drought.
Drought Avoidance
The ability of a plant to respond to drought conditions. This can be achieved by some of the following: closing stomata; reduced photosynthetic activity; folding or rolling of grass leaves; or reducing leaf area. All of these actions have the aim of reducing water loss. This can also be improved by a plant having an extensive root system or through a higher root to shoot biomass ratio.
Drought Escape
The ability of a plant to complete its life cycle before the commencement of drought conditions.
Drought Persistence
More commonly referred to as Drought Avoidance.
Drought Stress
The effect of very limited available water, typically during drier and warmer periods from May to September, to maintain plant health, resulting in wilting and depression of plant growth. Drought stress can affect small, irregular shaped areas, to entire area of a sports surface.