In Genesis, Noah’s dove returns with an olive leaf to show that the Flood waters are receding. Genesis 8:11 says the leaf is freshly plucked, giving Noah evidence that vegetation has reappeared above the waters.
The dove is sent after Noah first releases a raven. Noah later sends the dove repeatedly: it initially finds nowhere to land, then returns with the olive leaf, and finally does not return after being released again. These episodes form a sequence of practical observations about the changing landscape.
The olive leaf became a widely recognized symbol of peace, renewal, and hope. That symbolism is later reinforced by the rainbow covenant in Genesis 9, although the olive branch itself is not described there as a formal covenant sign. Ancient Mediterranean cultures also associated olive trees with prosperity and life.
The passage is sometimes paraphrased as “an olive branch,” but Genesis specifically says an olive leaf. The answer is therefore the leaf, not a branch or another type of vegetation.