From The Collaborative International Dictionary of English v.0.48 :
extremum \extremum\ n.
1. the point located farthest from the middle of something.
Syn: extreme point, extreme, extremity.
[WordNet 1.5]
2. the most extreme possible amount or value.
Syn: peak.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) :
extremum
n 1: the point located farthest from the middle of something
[syn: extreme point, extreme, extremum]
2: the most extreme possible amount or value; "voltage peak"
[syn: extremum, peak]