concomitant

Short definition from Wiktionary

Adjective

1. 1
   Accompanying; conjoining; attending; concurrent.
2. 2
   Of or relating to the grammatical aspect which expresses that a secondary action is occurring simultaneously to the primary action of the statement.

Noun

1. 1
   Something happening or existing at the same time.
2. 2
   An invariant homogeneous polynomial in the coefficients of a form, a covariant variable, and a contravariant variable.