<P> Usually these are the horizontal and vertical coordinates of a point in a two - dimensional rectangular Cartesian coordinate system . The terms can also refer to the horizontal and vertical axes respectively (typically x-axis and y--axis) of a two - dimensional graph . An ordered pair consists of two terms--the abscissa (horizontal, usually x) and the ordinate (vertical, usually y)--which define the location of a point in two - dimensional rectangular space . </P> <Dl> <Dd> (x ⏞ abscissa, y ⏞ ordinate) (\ displaystyle (\ overbrace (x) ^ (\ text (abscissa)), \ overbrace (y) ^ (\ text (ordinate)))) </Dd> </Dl> <Dd> (x ⏞ abscissa, y ⏞ ordinate) (\ displaystyle (\ overbrace (x) ^ (\ text (abscissa)), \ overbrace (y) ^ (\ text (ordinate)))) </Dd> <P> Though the word "abscissa" (Latin; "linea abscissa", "a line cut off") has been used at least since De Practica Geometrie published in 1220 by Fibonacci (Leonardo of Pisa), its use in its modern sense may be due to Venetian mathematician Stefano degli Angeli in his work Miscellaneum Hyperbolicum, et Parabolicum of 1659 . </P>

What do you mean by abscissa and ordinate