1.Definition: additional but secondary; auxiliary

2.Definition: descended from a common ancestor but through different lines

"Cousins are collateral relatives"

Related Adjective(s):indirect

3.Definition: occurring with or following as a consequence

"Collateral target damage from a bombing run"

Related Adjective(s):accompanying, attendant, concomitant, consequent, ensuant, incidental, resultant, sequent

4.Definition: serving to support or corroborate

"Collateral evidence"

Related Adjective(s):confirmative, confirmatory, confirming, corroborative, corroboratory, substantiating, substantiative, validating, validatory, verificatory, verifying

5.Definition: situated or running side by side

"Collateral ridges of mountains"