vlina gismu

x1 is a logical alternation/disjunction, stating that x2 (du'u) and/or x3 (du'u) is/are true.

See also kanxe, cmavo list a, ja, gi'a, gu'a.

In notes:

x1 is a conjunction, stating that x2 (du'u) and x3 (du'u) are both true.
at least one of the statements x1 (du'u) and x2 (du'u) is true (logical disjunction)