Tenma Defense is an Energy Shield used by Gohan.
Gohan charges his ki and lets forth a large white barrier to either knock away opponents or deflect attacks.
The first instance of Gohan using this technique was in Dragon Ball Z: Broly - Second Coming when he battled the maniacal Legendary Super Saiyan Broly. When the villain fired an Eraser Cannon at Gohan, he tried to deflect it into the air but it followed him back down again. Trying to stop the attack, Gohan used his Tenma Defense to stop the attack and defend his friends.
Appearances in Video Games
Tenma Defense was named in Battle of Z, where it appears as one of Adult Gohan's special attacks. When the attack is used near a teammate, the teammate is healed as well as himself.