Noah waited seven days before sending the dove out again from Noah’s Ark. Genesis 8:10 says that he waited another seven days after the dove’s first unsuccessful flight, then released it a second time.
That second flight produced the olive leaf, showing that the waters had receded and vegetation was available. Noah waited another seven days before releasing the dove once more, and the bird did not return.
The repeated seven-day intervals create a measured sequence within the flood narrative. They are separate from the forty days of rain and the 150 days during which the waters prevailed, so these numbers should not be merged into one timeline.
The passage uses seven days twice in the bird episode: once before the second release and again before the third. The answer to this question refers to the interval before the dove returned with the olive leaf.