An honorable mention is merely a name given to a distinction that may or may not be awarded at the end of a contest, exhibition, or competition. The definition implies that it is a distinction given to a entry worthy of mention, but not warranting top prize or first place. Depending on the rules and regulation of a given competition or contest, this may be the same as third to fifth place or may be part of an award given to a collective number of participants who rate the distinction.
Honorable mention can also be interpreted as runner-up status in a contest. Contests that award prizes for certain placements may award an this or a runner-up distinction to its participants. It could be simply the distinction or may include the same prize for all participants who earn that status at the end of the contest.
In exhibitions, honorable mention may be a better achievement than in prize contests. Literary and art competitions for example may award this to its entrants who do not take first place, but the exposure that results from the distinction is often beneficial. Many competitions at least make note of this award or awards in some fashion and, while not first place, can yield positive results such as public recognition, published recognition, or display and exhibition.
The sheer nature of contests warrants a competitive nature and honorable mention is obviously not the same as winning first place. However, in many competitions, it is considered placing or winning at some level. The actual distinction and the notoriety that may or may not come along with it depend solely on the rules and regulations as well as the nature of the contest or competition. Most competitors do not set out for achieving only honorable mention and strive to win, but in some venues, it is not the same as losing.