pe.ra.tsim is the proper place-name invoked as the setting for the LORD's rising up in Isaiah 28:21.

The attested use is a proper place-name: in Isaiah 28:21 it marks the mountain setting recalled for the LORD's rising up.

1. Place-name in a recalled divine action · dominant

   The form is tagged as a proper noun in Isaiah 28:21, where it occurs in the comparison for the LORD's rising up. In Isaiah 28:21 the APB renders the clause "as at Mount Perazim."

   Isaiah 28:21

In the Anselm Project Bible: In Isaiah 28:21, the APB presents the place-name in the phrase "Mount Perazim." The verse is read as a whole.