Units can be almost anything: adventurers, armies, balloons, bicycles, dragons, triremes, spiders, battleships, bridges, headquarters, cities. Units move around, manufacture things, fight with other units, and possibly die. They are the playing pieces of Xconq.
Units have a location, either out in the open terrain of a cell, or inside some other unit. In games that define connections, a unit may be on the connection rather than on the predominant terrain of the cell. (Think of a truck on a bridge.) There may be more than one unit in the open in a given cell, up to a game-defined limit. The collection of units sharing a cell is called a stack. A unit inside another unit is called an occupant in a transport, even if the "transport" is a type that can never move.
A unit's location may also include an altitude, expressed as its distance above the surface of the cell it is in. Altitude affects combat and viewing abilities.
A unit either belongs to a side, or else it is considered independent. Independent units do not do very much. In more complex games, the unit's side merely represents the current ownership, and the unit may have a range of feelings towards each side, including its current one. In those games, it is possible for one of your units to be a traitor!
Units can have a name, full name, and a number, as appropriate to the situation. The name is an ordinary name like "Joe Schmoe" or "Cincinnati", while the full name might be something like "Joseph P. Schmoe". The unit number, if used, is an ordinal that is maintained for each side and each unit type, so you can have both a "1st national bank" and a "45th infantry division" on your side. Names and numbers are always optional, and can usually be changed at any time during the game.
Every unit starts out with a number of hit points or hp representing how much damage it can sustain before dying. Certain types of units, such as armies and fleet of ships, have multiple parts, which means that damage to them reduces their effective size. In some games, you may be able to merge multi-part units into a single larger unit, and detach part of a multi-part unit. Damaged units may recover their hp on their own, or else be repairable by explicit action, either by themselves or by another units (ships in port for example).
In addition to occupants, a unit can also carry supplies (food, fuel, treasure, etc), which are type of "materials" (see the next section). Supplies are used up by movement, combat, and by just existing, and are gotten either by producing them or by transferring them from some other unit. Some games start units out with lots of supplies, while in others you have to acquire them on your own.
What a unit can do at any one time depends on the action points or acp available to it. Each sort of action - movement, construction, repair, etc - uses up at least one action point, and possibly more. A unit with an acp of 0 can never do anything on its own, although other units can still manipulate it. Also, not every type of unit can do every type of action; this is also defined by the game design. section Types of Actions lists all the types of actions that are possible in Xconq.
Units that engage in combat may accumulate combat experience or cxp for short. Combat experience will increase with each fight, irrespective of outcome, up to a game-defined maximum. An experienced unit will do better in combat, being both more effective in inflicting damage on opponents and at avoiding damage to itself.
You can lose a unit in many different ways: in combat, by running out of essential supplies, by being captured, by revolt, by garrisoning a captured unit, by leaving the world, or in accidents. If a unit dies because of excessive damage (i.e. hp = 0), then in some games it will change into its wrecked type. Wrecks are just normal units. For instance, a city might be "wrecked" and become a town. Occupants of dead or wrecked units will attempt to leave. If they can't, then they will share the fate of their transport. If an occupant can continue to occupy a wrecked transport with no problem, then nothing will happen to it.