des·i·nence 
(dĕsə-nəns)
(dĕsə-nəns)n.
A grammatical ending; an inflection.
[French désinence, from Medieval Latin dēsinentia, from Latin dēsinēns, dēsinent-, present participle of dēsinere, to come to an end : dē-, off; see DE- + sinere, to leave.]
des′i·nential (-nĕnshəl) adj.