orthogonal

Short definition from Wiktionary

Adjective

1. 1
   Of two objects, at right angles; perpendicular to each other.
2. 2
   Of a pair of vectors: having a zero inner product; perpendicular.
3. 3
   Of a square matrix: such that its transpose is equal to its inverse.
4. 4
   Of a linear transformation: preserving its angles.
5. 5
   Of grid graphs, board games and polyominoes: vertical or horizontal but not diagonal.
6. 6
   Of a pair of elements in an ortholattice: each less than or equal to the orthocomplement of the other.
7. 7
   Statistically independent, with reference to variates.
8. 8
   Of two or more aspects of a problem, able to be treated separately; of a design, exhibiting consistency and composability.
9. 9
   Of two or more problems or subjects, independent of or irrelevant to each other.

Noun

1. 1
   An orthogonal line.