The term Wrist computer refers to the specially-designed computer Orion (a.k.a. Stephen Bartowski) keeps on his left wrist during second season of Chuck.
The computer is able to perform such tasks as control MQ-1 Predator drones, send messages, override doors and security systems. The device can display the user's location inside a building with walls, doors, and nearby humans visible on-screen. The device was first seen in "Chuck Versus the Predator", and later appeared in "Chuck Versus the Dream Job" when Chuck's father revealed himself to be Orion. Towards the end of "Chuck Versus the Ring", Stephen gives the wrist computer to Chuck, but it has not reappeared in subsequent episodes which left many fans wondering what happened to it.
The computer may be a nod to the similar device worn by the titular aliens of the Predator series; or the Pip-Boy 3000 (of the Fallout video game series)
Also, the Data Glove Paired from the Call of Duty series may have been based on this, as Call of Duty premiered it approximately 3 years after it first appeared on Chuck, in the game Black Ops II.
This device may also be in reference to the the US Army's current exploration the concept of thin wrist-mounted displays that provide real-time UAV imagery.