ʿEd (H5707) refers to a witness — one who has seen and can testify. It is used in legal contexts (courts require two or three witnesses), in covenantal contexts (God as witness), and in prophetic contexts (Israel as God's witness to the nations). False witness is condemned in the ninth commandment.
ʿEd is a covenantal legal term with sweeping theological implications. God is the ultimate witness (Malachi 3:5; Micah 1:2). Israel is called to be God's witness to the nations (Isaiah 43:10–12). The ninth commandment protects truth-telling. And ultimately, Jesus identifies his disciples as martyres (witnesses) in Acts 1:8 — a direct echo of the Isaianic servant calling.