Random refers to when a card or cards are picked from a selection in a way such that the outcome is unpredictable.

The two main ways of doing this are as follows:

1. To hold the cards up, with their backs facing your opponent, and have them choose one at random.

2. Put them into a pile, shuffle them, and then take the desired/required number off the top.

Both of these methods are generally acceptable, although the second can be deemed to be more "purely random".

In the Yu-Gi-Oh! 5D's anime, the Duel Disk performs this function.