Brontē (βροντή) means thunder — the crashing sound accompanying lightning storms. In the biblical world, thunder was experienced as the voice or roar of God (Psalm 104:7; Job 37:4-5). In Revelation it frequently accompanies divine judgment and heavenly visions, expressing the awesome, fearful power of God.
James and John were called "Boanerges" — Sons of Thunder (Mark 3:17) — perhaps reflecting their fiery temperament or prophetic intensity. Thunder frames the great theophanic moments: at Sinai (Exodus 19:16), around God's throne (Revelation 4:5), and at the final judgment (Revelation 11:19). It is the sound of ultimate divine authority — God's voice as creation-shaking power.