adj

• (genealogy) Of an indirect ancestral relationship, as opposed to lineal descendency.
  "a collateral descendant"
• (finance) Relating to a collateral in the sense of an obligation or security.
• (finance) Expensive to the extent of being paid through a loan.
• (biology, of a vascular bundle) Having the phloem and xylem adjacent.

noun

• (finance) A security or guarantee (usually an asset) pledged for the repayment of a loan if one cannot procure enough funds to repay.
  ""The decline in the quality of eligible collateral is a grave problem. The ECB is now buying corporate bonds that are close to junk, and the haircuts can barely deal with a one-notch credit downgrade. The reputational risk of such actions by a central bank would have been unthinkable in the past.""
• (now rare, genealogy) A collateral (not linear) family member.
• (anatomy) A branch of a bodily part or system of organs.
  "Besides the arteries blood streams through numerous veins we call collaterals."
• (marketing) Printed materials or content of electronic media used to enhance sales of products (short form of collateral material).