ex·tre·mum 
(ĭk-strēməm)
(ĭk-strēməm)n. pl. ex·tre·ma (-mə)
Mathematics
Mathematics
A value in the domain of a given function at which the function attains a maximum or minimum value.
[From Latin, extrēmum, neuter sing. of extrēmus, outermost, extreme; see eghs in the Appendix of Indo-European roots.]