shi-ga'-yon, shi-gi'-on (shiggayon): Occurs in the title of Ps 7, and, in the plural, in the verse introducing Habakkuk's prayer (Hab 3:1). Derived from a verb meaning "to wander," it is generally taken to mean a dithyramb, or rhapsody. This is not supported by the Greek VSS, but they are evidently quite at a loss.

from the International Standard Bible Encyclopedia (public domain)

Psalm 7:1 and Habakkuk 3:1