Air dome: A structure that is inflated and when erected acts as an enclosure for a swimming pool or other structure, such as a tennis court. The convenience of an air dome is that in the summer it can be taken down, but also can lengthen swimming time year round since it can remain up in the winter.
Automatic cover: Solid, reinforced vinyl that rolls onto a reel on one end of the pool and attaches on the sides into small aluminum tracks. An automatic cover can be motorized, or feature a hand crank. Some models may snap the sides into small anchors placed into the deck for more flexibility when it comes to pool shape. Automatic covers enable safe surroundings (with water pumped off); debris protection; and heat/chemical/water retention.
Debris cover: Debris covers typically are attached all winter by hooked bungee cords or hooked springs connected to the pool deck, and usually are made of black or green fine PVC mesh. They are designed to stop leaf debris from entering the pool. They also provide some safety for animals and small children, but should not be relied on. They are not popular in warmer climates, due to the five to 10 minutes it takes to fit/remove, making them inconvenient for repeated application and removal.
Hard cover: A cover that rests on the edge or coping of the spa or small pool. A hard cover provides a barrier to debris and possibly people, while keeping the heat trapped in.
Hemming: The hemming is the finished edge, and is an option on covers. It is sewn onto the perimeter of the cover and improves the life expectancy as it protects the cover from wear and tear at the edges.
Leaf net: A lightweight cover made of an open weave material that fits over a winter cover or solar cover to prevent accumulation of wet, heavy, saturated leaves and twigs on top of the cover. A leaf net ensures faster removal of leaves, and prolongs the life of a winter or solar cover. Â It can be used in any season, and is a big plus if a pool is located in an area surrounded by trees. The open weave design allows water to pass through the net, but will block twigs and trash. Leaf nets facilitate the removal of a pool cover every time.
Mesh cover: Flexible mesh covers stretch tightly across the pool like a trampoline. These are the only covers that can be called safety covers in that the mesh polypropylene allows precipitation to pass through.
Safety cover: Available in rugged mesh or a solid material, these covers function as a maintenance tool as well as a safety barrier. All safety covers must meet the requirements in the ASTM standards F1346-91 (1996) meaning the cover must be able to support the weight of a small child or animal that may walk onto the cover. A proper safety cover is securely anchored into the deck area surrounding the pool and lies flat so there are no gaps between the pool and the cover. A good safety cover will provide peace of mind if it is made from material that will not run, so that a hole will not increase in size and instead can be patched. Safety covers follow the shape of the pool with the proper number of anchors embedded around the pool to hold the cover in place.
Solar cover: Sometimes called a solar blanket, a thermal blanket, a pool blanket, and a bubble cover, this cover floats on the surface, magnifying the sun's rays to warm the water and prevent chemical/heat/water evaporation.
Solid cover: Solid covers usually are made of some form of plastic or vinyl, and are secured around the edges by aqua blocks or similar weight, or the edges attach to anchors set in the concrete or wood deck.
Winter cover: A barrier to sun and debris, winter covers secure the pool from contamination. A winter cover is secured around the perimeter of a pool, spa, or hot tub, forming a barrier to bathers and debris when the pool, spa, or hot tub is closed for the season.
Winterized pool liner: Plastic liners designed to tolerate exposure to severe winter temperatures.
Winterizing: The process of preparing pools and spas- as well as all associated equipment, including pool pumps, filters, and heaters- for winter.
Editor's note: Taken from sources found at
http://www.havuz.org/pool-glossary.htm
http://www.1st-direct.com/swimming-pool-glossary.htm
http://www.pcpools.com/poolq4.aspx
http://www.poolcoversource.com/pool-cover-history