As nouns the difference between concomitance and concomitancy
is that concomitance is occurrence or existence together or in connection with one another, co-existence while concomitancy is the condition of being concomitant.
concomitance
English
Noun
(
en noun)
occurrence or existence together or in connection with one another, co-existence
a concomitant
concomitancy
English
Noun
(-)
The condition of being concomitant
concomitance