sir.yon denotes protective military equipment worn by combatants in battle preparations.

The two verses use the term for protective military equipment in battle contexts: it is put on with helmets and spears in Jeremiah 46:4, and an archer is described in relation to it in Jeremiah 51:3.

1. Protective equipment for battle · dominant

   In Jeremiah 46:4, the plural absolute form occurs in commands to prepare horses, helmets, and spears; the APB renders the final command, “put on the armor.” In Jeremiah 51:3, the singular construct form occurs in the instruction concerning an archer; the APB renders, “let him not rise in his armor.”

   Jeremiah 46:4Jeremiah 51:3

In the Anselm Project Bible: The APB presents the term as “armor” in both verses, within commands and descriptions of military action. It confirms the battle setting without isolating every grammatical contribution of the Hebrew form.