The 20th letter (Y, y) of the Greek alphabet, a vowel having originally the sound of oo as in room, becoming before the 4th century b. c. that French u or Ger. ü. Its equivalent in English is u or y.

Style of Maze composed of interlocking octagons and squares. Name comes from the shape of the capital Greek letter Upsilon, whose "Y" shape is similar to angles seen in these Mazes. See also Omega.

Upsilon (upper case Υ, lower case υ) is the 20th letter of the Greek alphabet. In the system of Greek numerals it has a value of 400. It is derived from the Phoenician waw.

adverb - One of the two directions pointing out of realmspace into tetraspace; movement in the positive w direction. In tetraspace, represented by the vector 0,0,0,1. This term refers to the direction analogous to up; the 'u' in 'upsilon' corresponds to the 'u' in 'up'. In some literature, this direction is referred to as kata. This term is the same direction as wint, but is used in a different context: upsilon is movement from realmspace to tetraspace, but wint is a turning direction. The opposite direction is delta. See the chart under direction.