Standby

[Sarah]

When electronic devices are receiving power but are not running, they are in standby mode. For example, a television is in standby mode when it is plugged in, but turned off. While the TV is not on, it is ready to receive a signal from the remote control. An A/V receiver is also in standby mode when it is plugged in and turned off. This is because the receiver may be activated by receiving input from a connected device or by being turned on directly with the remote control. In other words, these devices are standing by, waiting to receive input from the user or another device.
When a computer is in standby mode, it is not completely turned off. Instead, it has already been turned on, but has gone into sleep mode. Therefore, when referring to computers, Sleep and Standby may be used synonymously. A computer in standby mode requires a small amount of current, called a trickle charge, that keeps the current state of running software saved in the computers RAM. However, because the computer is in sleep mode, the CPU, video card, and hard drive are not running. Therefore, the computer uses very little power in standby mode.
Since standby mode saves energy, it is a good idea to put your computer to sleep if you are going to be away from it for more than 15 or 20 minutes. You can also use the Power Options control panel (in Windows) or the Energy Saver System Preference (in Mac OS to automatically put your computer to sleep after it has been inactive for a specific amount of time. Then, when you take a break from your computer, your computer can take a break as well.

[Oralee]

Readiness for duty or immediate deployment.

[Mary Mallozziberg]

The act of pausing, or standbying the connection in an online game, primarily on Halo2. When standbying, the host of the game (the player that the other players are connected to) causes all of the other plays to lag into a Blue screen which is the Connecting to Game screen. The host, however, gain a few more seconds of [Game-time] before he himself is also put into blue screen. Expert standbyers are able to kill every person on the opposing team without ever going to [Bluescreen].
There are different types of [Standby], Normal [standby], in which just one player does it, and Team standby, in which the entire team (or multiple people on that team) [bridged] their connections together and are both standbying which is also a lot more effective and a lot harder to [lag out] of.
Standby is done primarily in two fashions:

Pushing the Standby button your modem.
Unplugging your [Ethernet] cord out of your modem.

However, some more intelligent people find easier ways of doing this, one being [UDP] Packet Flooding (My favorite).
Although Standbying is cheating, some people standby only when they are being modded. Standby causes all of the [modders] abilities (super speed/jump/[auto aim]) to stop briefly, usually within enough time to kill him.
Standbying ends then the host either lags out of the game (and you see a Re-establishing Connection screen), or when the host pushes the Standby button again/plugs his [ethernet] back in.
Only hosts can standby.

[Monty]

Be present while something bad is happening but fail to take any action to stop it.