Is the middle passage the triangle passage?

Not exactly. The Middle Passage was a part of the Triangular Trade (more prefferably than "Triangular Passage"). And this Triangular Trade was an international trade network at that time, among Europe,Africa,and America. It had three legs, or parts. The Middle Passage is the second leg, and also the most important. It is where the African slaves were exchaged for European goods like guns and crops.