# Definition of abscissa in US English:

## abscissa

### noun

Mathematics
• (in a system of coordinates) the x-coordinate, the distance from a point to the vertical or y-axis measured parallel to the horizontal or x-axis.

Compare with ordinate
• ‘To unify the curves to a single abscissa, we define a nominal maximal velocity for W / T e = 1, [beta] = 1, and y = 4.5.’
• ‘Open and closed time histograms were plotted using a logarithmic abscissa and a square root ordinate and fitted to the sum of exponential functions by maximal likelihood using the program TACFit (Bruxton Corporation, Seattle, WA).’
• ‘Plotted on the abscissa of the graph are the incompatibility values or the proportions of informative sites incompatible with the particular clade in the set of artificially generated sequences.’
• ‘Here, the amplitude of the eigenvector in the lowest-frequency mode is plotted on the ordinate whereas the abscissa shows the residue number.’
• ‘That is to say, the intercepts on the abscissa and the ordinate should be higher for isocline 2 at x = 1.’

### Origin

Early 17th century (denoting the part of a line between a point on it and the point of intersection with an ordinate): from modern Latin abscissa (linea) ‘cutoff (line)’, feminine past participle of abscindere (see abscission).

## abscissa

/æbˈsɪsə//abˈsisə/