chro·nax·ie also chro·nax·y 
(krōnăk′sē, krŏnăk′-)
(krōnăk′sē, krŏnăk′-)n. pl. chro·nax·ies
The minimum interval of time necessary to electrically stimulate a muscle or nerve fiber, using twice the minimum current needed to elicit a threshold response.
[French : Greek khronos, time + Greek axiā, value (from axios, worthy; see ag- in the Appendix of Indo-European roots).]