-ency

1.
a noun suffix, equivalent to -ence:
consistency; dependency; exigency.
Origin
-ence + -y3
British Dictionary definitions for -ency

-ence

suffix
1.
indicating an action, state, condition, or quality: benevolence, residence, patience
Word Origin
via Old French from Latin -entia, from -ēns, present participial ending

-ency

suffix
1.
a variant of -ence fluency, permanency
Word Origin and History for -ency

word-forming element denoting quality or state, from Latin -entia. Derivatively identical with -ence.