In Arelith, each area has certain "flags". You see which flags are active whenever you enter a new area (they appear as words in square brackets (). Each has its own meaning, but the meanings are not readily apparant. This article should give you a better idea of what each flag means.
Off by default, [PvP] indicates that any players killed in this area will not immediately be sent to the Death area, but will get up on one hit point after a delay of 20 seconds. The normal death penalties do not apply, and experience is not gained for killing players' character. This is intended to be used in arena-type areas, where characters may face off against one another in a safe environment, in the knowledge that none of the attacks there are going to be lethal.
The [Rest] flag indicates that the area can be rested in comfortably. Designed primarily for inns and similar areas, [Rest] allows one to rest no matter what their tiredness state percentage is (normally one would have to be below 50% to rest). This is off by default.
The [Magic] flag indicates that the area contains the presence of the Weave. Mechanically, this means that spells can be cast in the area. Areas without the [Magic] flag are considered "dead" magic and are quite rare. This flag is on by default.
Every hour, a character is given bonus experience according to their Roleplaying Bonus, and their hunger, thirst and fatigue state values fall slightly. This only happens in areas with the [State] flag enabled: areas such as the entry area and the Death area do not have [State] enabled. The only in-character area with [State] disabled is Death; everywhere else hunger, thirst and fatigue act normally, with exception of certain inns and bars.
Portals are fairly common on Arelith, and the Portal Lens item allows one to teleport to a known portal at will. This can be done in all areas with the [Teleport] flag enabled; if it is disabled then teleporting is impossible. This also applies to the -teleport and -yoink console commands. It is enabled by default in most areas.
[Transfer] indicates that a character can lose his or her items. It is enabled in almost all areas; Death being a notable exception. If this flag is disabled, items cannot be transferred between players or dropped. In addition, trap kits cannot be set. This is enabled by default.
As opposed to [PvP], [Death] simply indicates that a character can be killed. If [Death] is disabled, all PCs in the area are immortal which means that they can be damaged but can never be killed. [Death] is enabled by default.
Many of these are simply common sense settings for various areas. However some, such as [Magic], can be dynamic. DMs have the ability to change any of these flags in any area at will, so if, for example, a DM-possessed mage was warding an area against further spellcasting in a scene, that can be achieved by simply switching [Magic] off.