A small or high obstacle which horses jump over.

Timber-framed obstacle interlaced with gorse and birch and measuring a minimum of three foot six inches high.

an obstacle that you are expected to overcome; "the last hurdle before graduation"

the act of jumping over an obstacle

The last portion of the diver's approach, on which he or she springs off one foot toward the end of the board and lands on both feet.

The last part of a diver's approach to a forward facing take-off, where the final step starts from one foot and ends on two feet before leaving the board.

The transitional motion from a run to set up to perform a skill. This hurdle can be from one foot to two feet, or one foot to one foot, or in the case of a "jump hurdle" or "power hurdle" from two feet to one foot. In the case of floor setting up for a right round-off, handspring or other kicking skill the hurdle is a skip on the left leg while stretching and bringing the right leg forward to prepare for the lunge. In the case of vault, or two foot take-off skill on floor the hurdle is a low jump from one foot to two feet bringing both feel forward to maximize conversion of forward momentum into height. In all cases a proper powerful hurdle is critical to the performance of many high level skills.

An obstical (with a bar at the top about 2 ¾" in width) a runner must clear by striding or jumping. The height of the bar varies depending on the event (high hurdles:36 inches high, intermediate hurdles: __"; low hurdles: 30 inches high). An athlete must make a bona fide attempt to clear the hurdles (cannot run around it or intentionally knock it down, or impede a different runner).