e·qua·nim·i·ty 
(ē′kwə-nĭmĭ-tē, ĕk′wə-)
(ē′kwə-nĭmĭ-tē, ĕk′wə-)n.
The quality of being calm and even-tempered; composure.
[Latin aequanimitās, from aequanimus, even-tempered, impartial : aequus, even + animus, mind; see anə- in the Appendix of Indo-European roots.]