Source : Webster's Revised Unabridged Dictionary (1913)

Pentose \Pen"tose\, n. [Penta- + -ose.] (Chem.)
   Any of a group of sugars of the formula {C5H10O5}, as
   arabinose; -- so called from the five carbon atoms in the
   molecule. They are not fermented by yeast.

Xylose \Xy"lose\, n. [Pref. xylo- + -ose.] (Chem.)
   An unfermentable sugar of the pentose class, {C5H10O5},
   formed by the hydrolysis of xylan; wood sugar.

Arabinose \Ar"a*bin*ose`\, n. (Chem.)
   A sugar of the composition {C5H10O5}, obtained from cherry
   gum by boiling it with dilute sulphuric acid.