Texture (Grass) - The coarseness or fineness of a turfgrass generally based on the grass blade width and the stem size.

Texture (Soil) - The relative proportion (expressed as a percent) of sand, silt, and clay particles in a soil; determines soil coarseness or fineness.

Thatch - A dense, fibrous layer of living and dead grass stems, leaves, and roots, undecomposed or partially decomposed, that accumulates between the green vegetation and soil surface.

Tiller - A lateral shoot, usually erect, that develops from axillary buds in the crown.

Tolerance - The plant's ability to withstand stresses associated with unfavorable environmental conditions or the application of pesticides.

Topsoil - The upper portion of soil that is generally higher in organic matter in comparison to the subsoil and usually has more favorable characteristics of soil fertility, aeration and structure.

Transpiration - Water loss that occurs through the open plant stomata (tiny pores primarily on the underside of the leaf). Rate of loss is determined by wind and atmospheric humidity conditions.

Turf - A soil covering of mowed vegetation, usually a turfgrass.

Turfgrass - A species or cultivar of grass that is maintained at a desired height through regular mowing.

Urea - A quick-release nitrogen fertilizer source. Usually available as 45-0-0 or 46-0-0. It is also described as a synthetic organic fertilizer as it contains the element carbon in its chemical structure.

Variety - A population of plants having many characteristics in common; a variety may be a pure line, a mixture of pure lines, or a clone.

Vertical Mower - A machine with high-speed, vertically rotating blades that slice into the turf for the purpose of reducing thatch or improving soil aeration.

Vigor (Plant) - The combination of genetic and environmental factors that determine the rate and amount that a turfgrass species or cultivar is able to grow and spread.