A showjump fence that consists of poles directly above each other with no spread or width, to jump.
Vertical (or upright) - A showjump fence that consists of poles directly above each other with no spread or width, to jump.
Oxer - Basically the oxer showjump has two verticals placed reasonably close together to make the jump wider.
Square oxer (sometimes known as Box Oxer): both top poles are of an equal height
Ascending oxer (usually called a Ramped Oxer): the furthest pole is higher than the first
Descending oxer (usually called an Offset Oxer): the furthest pole is lower than the closest
Swedish oxer: the poles slant in opposite directions, so that they appear to form an "X" shape when seen head on.
Triple Bar - The tripple bar has three poles placed across to produce a wide spread or oxer.
Cross Rail - not commonly used in sanctioned horse shows, and sometimes called a "cross-pole," two poles crossed with one end of each pole being on the ground and on jump standards so that the center is lower than the sides
Wall - This type of showjump is usually made to look like a brick wall, however the "bricks" are constructed of a lightweight material and fall easily when knocked by the horse.
Hogsback – a type of spread fence with three rails where the tallest pole is in the center
Combination – usually two or three jumps in a row, with no more than two strides between each. two jumps in a row are called double combinations, and three jumps in a row are called triple combinations
Fan: the rails on one side of the fence are spread out by standards, making the fence take the shape of a fan when viewed from above
Open Water - A wide ditch of water. The water can be open or have a jump at the entrance or exit.
Liverpool - A liverpool showjump is simply a ditch of water placed under a vertical or an oxer.
Joker – a tricky fence comprising only a rustic (or unpainted) rail and two wings wherein the lack of filler makes it difficult for a horse to judge their proximity to the fence as well as the fence's height, making it a tricky obstacle usually found only in the upper divisions, and illegal in some competitions.
At international level competitions that are governed by FEI rules, fence heights begin at 1.50 metres (4 ft 11 in).
Equestrian Summer London Olympics 2012 are scheduled to be held between 28 July and 9 August, at the Greenwich Park venue in London.