x1 is a relation space formed from elements/nodes in set x2 and relationship x2 which connects them.
x1 is a space/directed graph/set of ordered n-tuples which is formed from the endowment of of a space/set (of possible nodes) x2 with the relationship x3 which is n-ary. Suppose that x2 is binary; let y and z be elements in x2 and denote x3 by "R" so that "a R b" means that R relates 'a' to 'b' in that order (not necessarily the reverse); then: if y R z, then (y,z) is an element in x1. In other words, x1 is the set of exactly all ordered edges between members of x2 (which are nodes/endpoints of members of x1), which are formed iff R relates those members in the order indicated by the direction of the edge (source then destination; first term, then second term) when R is binary. Greater arity is possible (in which case ordered n-tuples become useful and edges scale up dimensionally). x1 is the set of all ordered relationships in x2 formed by x3. One valjvo of this word is an experimental gismu: grafu.