Filled Surface 
A synthetic grass carpet which has had a material applied to it. Traditionally the fill material would be sand, and a filled surface would mean to fill the carpet close to the surface of the pile height, typically within 2mm or 3mm of the tips, but at least to 80% of the pile height. The pile length for a filled surface can be quite variable.
First Generation Pitch (1G)
The initial type of synthetic grass carpet (from the mid-1960s to the early 1980s) which was made of polyamide (nylon) and which produced a coarse, fairly unforgiving surface. These surfaces did not have any infill material, but in some cases did have water applied to make them less liable to causing friction burns on players.
Football Turf
A term used by FIFA and UEFA to refer to a synthetic turf surface which has similar test performance criteria to those of good natural turfgrass surfaces.
Fourth Generation Pitch (4G)
A marketing term which is used to sell 3G sports surfaces. As of 2020 there has been no significant innovation in 3G sports surfaces which could justify recategorizing them as 4G. A synthetic carpet has, however, been manufactured with very dense tufts, often being of more than one shade of green and also including a light brown colour to imitate some basal grass sheaths. These are very dense carpets and not designed to have any infill material applied, which can be a distinct advantage. However, the significant limitation of these carpets is that of without any infill material how can the str
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Free Pile Height
Geotextile
A permeable fabric which can be used for several purposes. It might be placed on top of soil to act as a weed suppressant and may also then covered over with bark or gravel. It might be placed at the base of drainage runs; as wrapping around some drainage pipes; as a layer between soil and gravel, or similar situations. A geotextile can help to reduce finer materials filtering down and contaminating lower profiles.
Grass Carpet
A general term for a Synthetic Turf Surface.
Hard Porous
A non-turf, artificial, surface, which is a by-product of the quarrying of rock, being composed of a range of particle sizes, and being angular to sub-angular in shape. Initial constructions would have had good drainage rates, however, over time the particles would break down and more fines would become present within the surface hard porous layer resulting in a reduction in drainage and increase in surface ponding.
Hybrid Turf
A marketing term which is used to describe reinforced turf.
Infill
A material which is used for adding to a synthetic carpet and to be worked in amongst the fibres to assist in keeping the fibres upright. An infill material might be sand, rubber crumb or an organic infill such as cork.