Acidic relates to the pH scale where a measurement of the shrimp tank water under 7 is considered "acidic" and over 7 as "basic or alkaline" and 7 is considered "neutral".
Activated Carbon sometimes abbreviated as "AC", this is a form of carbon that is used in aquariums to remove dissolved nutrients and contaminates. Only issue with using activated carbon is it needs to be replaced every month or you run the risk of leaking back out contaminates.
An aquarium air pump is a device used to force air into aquarium tubing. The tubing is placed into the aquarium (used in conjunction with an air stone) to increase water agitation and increasing the dissolved oxygen level in your tank.
An air stone is used in conjunction with an air pump and tubing, the air stone is placed at the end of the tubing in the tank. These "stones" produce lots of small air bubbles which float upwards causing the waters surface to become agitated and thus increasing the dissolved oxygen levels in the water.
Aeration is usually referred to in the context of "you need to increase the aeration in your tank". This means that you need to increase the surface agitation by using a device to agitate the surface of the tank water. You can do this by using air stones, power heads pointed at the water surface, and via return filters or other aquarium pumps.
Algae can be both simple and complex in form with varieties growing on nearly any surface within an aquarium. There are brown diatoms, blue-green algae, green algae and red algae. Algae needs nutrients such as carbon dioxide, phosphates and nitrates to grow.
Alkaline relates to the pH scale where a measurement of the shrimp tank water is over 7 and is considered "basic or alkaline".
Alkalinity you'll usually hear reef keepers discussing. Alkalinity is basically a measurement of how well the water in your aquarium can buffer against a drop in pH. An alkalinity test kit will measure the levels of elements such as carbonates, bicarbonates and some other elements. It is usually measured in units of meq/L or ppm which are essentially the same.
Abbreviated as NH3 (one part nitrogen and 3 parts hydrogen), ammonia is released into the aquarium from uneaten foods, dead shrimp, shrimp wastes and other biological processes. It is easily measured using an aquarium test kit and is the first reading you'll get at the beginning of the aquarium nitrogen cycle. Ammonia is always being released into the aquarium and adequate biological filtration is needed to prevent the life forms from suffering because it is very toxic to shrimp. Ammonia is thought to be the number one killer of shrimp in aquariums, most likely due to aquariums going through the nitrogen cycle.
Anaerobic means that there is no oxygen is present or an organism does not require oxygen.
Anchialine pools are tidally influenced saline pools that occur along the coast but are not openly connected to the ocean. This includes water in natural depressions, fissures, quarries, and craters.
Aragonite is a form of calcium carbonate, this term refers to a substrate used in the aquarium to raise or maintain high pH and alkalinity levels.