Source : Webster's Revised Unabridged Dictionary (1913)

Distension \Dis*ten"sion\, n.
   Same as {Distention}.

Source : WordNet®

distension
     n 1: the act of expanding by pressure from within [syn: {distention}]
     2: the state of being stretched beyond normal dimensions [syn:
        {dilatation}, {distention}]