con·com·i·tant 
(k
ən-k
ŏm
ĭ-t
ənt)
adj. Occurring or existing concurrently; attendant: poverty and its concomitant social problems. See Synonyms at contemporary.
n. One that occurs or exists concurrently with another.
[Late Latin concomitāns, concomitant-, present participle of concomitārī, to accompany : Latin com-, com- + Latin comitārī, to accompany (from comes, comit-, companion; see ei- in the Appendix of Indo-European roots).]
con·comi·tant·ly adv.