Collateral meaning : A security or guarantee (usually an asset) pledged for the repayment of a loan if one cannot procure enough funds to repay. (genealogy) A collateral (not linear) family member. A branch of a bodily part or system of organs. Printed materials or content of electronic media used to enhance sales of products (short form of collateral material). A thinner blood vessel providing an alternate route to blood flow in case the main vessel becomes occluded. A contemporary or rival. Parallel, along the same vein, side by side. Corresponding; accompanying, concomitant. Being aside from the main subject, target, or goal. (genealogy) Of an indirect ancestral relationship, as opposed to lineal descendency. Relating to a collateral in the sense of an obligation or security. Expensive to the extent of being paid through a loan. Coming or directed along the side. Acting in an indirect way. (of a vascular bundle) Having the phloem and xylem adjacent.