正交

正交	zhèng jiāo	orthogonality
正	zhēng	first month of the lunar year
正	zhèng	straight / upright / proper / main / principal / to correct / to rectify / exactly / just (at that time) / right (in that place) / (math.) positive
交	jiāo	to hand over; to deliver; to pay (money); to turn over / to make friends / (of lines) to intersect / variant of 跤