collateral

Concise Oxford English Dictionary © 2008 Oxford University Press:
collateral /kɒˈlat(ə)r(ə)l/

▶noun

• 1 something pledged as security for repayment of a loan.

• 2 a person descended from the same ancestor as another but through a different line.

▶adjective

• 1 descended from the same stock but by a different line.

• 2 additional but subordinate; secondary.

• 3 situated side by side; parallel: collateral veins.

– derivatives
collaterality noun,
collaterally adverb.

– origin ME: from med. L. collateralis, from col- ‘together with’ + lateralis (from latus, later- ‘side’).