What does ‘ran out’ mean?

What does 'ran out' mean? During a race, if a horse, with its jockey intact, takes the wrong course or bypasses an obstacle by running around it, rather than jumping over it, that horse is said to have ‘run out’ and is immediately disqualified. Thus, the in-running comments for the horse in question may include something along the lines of ‘…ridden 3 out, weakened next, ran out approaching last’ and its form figures will include a letter ‘O’ to indicate what happened. Note that ‘ran out’ is slightly different from ‘carried out’ – indicated by a letter ‘C’ in the form figures – where a horse is sufficiently impeded by a rival that it is carried off the course through no fault of its own.

A horse taking the wrong course is often the result of jockey error. While inexcusable, such errors used to be a regular occurrence on the Cross Country Course at Cheltenham, for example, which twists and turns and doubles back on itself at various points. However, it is not uncommon for a horse to hang violently one way or the other, sometimes to the point that it becomes difficult, or impossible, for its jockey to control. In such cases, it may be impossible for a jockey to prevent a horse running out and, in fact, this may be the safest option for all concerned.