The Hebrew word ethan (אֵיתָן) means "ever-flowing, perennial, constant, perpetual." It is used of streams that never run dry and, metaphorically, of strength that endures. As an adjective it appears in contexts describing reliable water sources. As a proper name, Ethan was a renowned sage of Israel.
The word ethan describes the quality of permanent, inexhaustible flow — the kind of stream that does not dry up in summer drought. Theologically, this quality is attributed to God's covenant love: chesed that is ethan — steadfast and never failing. Ethan the Ezrahite was one of Israel's wisest men (1 Kings 4:31) and is credited with Psalm 89, a meditation on God's unfailing covenant with David. Even when circumstances seemed to contradict the promise, Ethan declared: "Your love, O LORD, forever will I sing."