A unique set of kin-terms common in some Australian Aboriginal languages are tri-relational—also called triangular, ternary, triadic and shared kin-terms—which encapsulate a set of relations between three distinct entities. Broadly, there are two kinds of tri-relational kin-terms. The more common is a "Dual Propositus Tri-relational Kin-term" which has one referent whose relationship is defined with respect to two anchor points ("propositi") and from which the relation between the two "propositi" can be inferred. The less common are "Tri-relational Dyadic Terms" which reference a pair of related entities which (i.e., this dyad) is in some way to single "propositus".