Final answer:
The technique that involves crossing two strands of hair to opposite sides to create a crisscross effect is known as a French braid.
Step-by-step explanation:
The long hair technique described in the question is known as a French braid. This style involves taking two strands of hair and crossing them over to the opposite sides, either in a downward or upward direction, to produce a crisscross effect that resembles the pattern of a braid. The French braid is different from cornrows, dreadlocks, and beehive hairstyles, each of which has a distinctive look and method of creation.