anything, place, country, &c. situated by the side of another.
in genealogy, those relations which proceed from the same stock, but not in the same line of ascendants or descendants, yet are as it were beside each other. Thus uncles, aunts, nephews, nieces, and cousins, are collaterals, or in the same collateral line. Those in a higher degree, and nearer the common root, represent a kind of paternity with regard to those more remote.
COLLATERAL Succession. When a defunct, for want of heirs descended of himself, is succeeded in his estate by a brother or sister, or their descendants, the estate is said to have gone to collateral heirs.