As it appears in the campaign world of Tolrea, the monk class of the Dungeons and Dragons v.3.5 Core Rules might be described more precisely as a class for unarmed martial artists. Not all monks of the kind who inhabit monasteries are members of the monk class, and not all members of the monk class are monastic in character.
Putting aside semantics, most of Tolrea's oldest styles of unarmed martial arts originated and are practiced in communities of fighting monks. The Mereflow Valley's elves, dwarves, gnomes, and halflings have no monastic traditions to speak of, although there have been members of all four races who have undertaken the study of the martial arts as practiced by various teachers who have entered the region since its colonization by the human-dominated Aureshan Empire. Monastic traditions of the martial arts do exist for all four of these races in other parts of the world.
Most of the traditional styles of unarmed combat in the Aureshan Empire are tied to the churches of Oceus, Merthia, Agon, and Lereina. A few hidden monasteries of Ekar also exist within the Empire, but little is known about the nature of the training administered within their confines. A tradition of wandering monks, friars, and mendicant priests also flourishes in the Empire, especially in the service of Herenus the Mariner. In the cases of both cloistered and traveling monks, it is commonplace to multiclass as a cleric/monk or a monk/fighter. Monk/paladins are occasionally seen in the churches of Agon and Merthia; Herenus's mendicant friars sometimes also multiclass as monk/rangers.
A secondary but still important strain of monasticism also exists in the Aureshan Empire, associated with a variety of druidic sects whose histories date back to before the start of recorded history. This group of martial art forms is often named for an animal, magical beast, or other monster from the movements of which a given style was inspired. Monk/rangers and druid/monks are common in many of these styles, and practitioners of races other than human, half-elf, and half-orc are much more common in these traditions. This variety of fighting monk is becoming less and less common in the Aureshan Empire's sphere of influence, in large part because of the rapid growth of the human population. As the Empire has grown more settled and civilized, druids have found it less hospitable. Many orders have chosen to move to frontier areas on the periphery of the Empire, but a few attempted to fight instead, with the result that several of the oldest known schools of martial arts were utterly destroyed in battle against the Imperial Legion.
Finally, a variety of martial arts schools have splintered off from both the religious and the druidic styles as disciples have been expelled from or simply left monastic life; sometimes the reason for this is as simple as an inability to submit to the rigorous discipline of monastic life, so that a student is unable to continue training because he or she is no longer lawful, but at other times a student quarrels with his or her teachers and decides to fend for himself or herself. A few itinerant martial artists also roam the Empire and its colonies as fugitives since their schools were brought down by the Legion. Many hybrid styles have come into existence as a result of these non-monastic monks' occasional efforts to train disciples of their own, and some have been transmitted as family or regional styles. These are seldom well-known outside of the source from which they originate.
In Mereflow Valley, most monks are stylists of the non-monastic schools, although there is a number of fighting monks and friars of the religious schools (or "temple" schools, as they are sometimes called) as well, especially in and near Port Hope. The druidic or "sectarian" styles are not as well represented in settled areas, but there are a few secluded monasteries of these styles scattered through the area. Monks and friars of the temple schools usually do not teach their arts to anyone who is not a novice of their own order, and the sectarian stylists are even more secretive, but non-monastic artists are frequently willing to teach anyone who can pay. As a result, there are self-styled "martial artists" in Port Hope who are not monks; it is currently fashionable amongst wild young men, aristocrat and commoner alike, to learn "Aureshan boxing." A typical student of this sort frequently is not lawful, and may be nothing more than a 1st-level commoner with Improved Unarmed Strike and proficiency with his bare hands. Such rowdies offer little threat to an armed and armored adventurer, but are more than capable of slaying the average man in the street. More advanced students of this ilk may garner sufficient training to master Improved Grapple or parts of the Combat Expertise feat tree, or even gain the Stunning Fist feat, but they're rare.
Martial Arts Styles: The pursuit of martial arts training according to school or style confers benefits beyond those afforded simply by taking levels in the monk class and choosing feats according to one's own plans.
The Sectarian Styles: Many of these schools require training in the druidic mysteries to master. Advanced practitioners of the sectarian styles expand the boundaries of the wild shape ability.
The Temple Styles: True mastery in these styles often requires training as a cleric or paladin, since the temple schools were developed by and for the clergy of the Celestial Court.