According to Genesis, a rainbow symbolized God’s covenant after Noah’s Ark. After Noah left the vessel and made an altar, God established a covenant with Noah, his descendants, and every living creature.
Genesis presents the rainbow as a sign that the earth would not again be destroyed by a flood of that kind. The covenant is therefore broader than a private promise to Noah: it includes future generations and the animal world. The text describes the rainbow appearing in the clouds and serving as a reminder of the covenant.
In later culture, the rainbow has acquired many additional meanings, including peace, hope, and diversity. Those meanings are not identical to the specific covenant role in Genesis, though they often draw on the same association with reassurance after a storm.
The rainbow appears after the Ark narrative’s rescue and survival scenes, not as a signal used to guide the Ark during the flood.