Final answer:
The best meaning of impression in the article is a first idea about something.
Step-by-step explanation:
The best meaning of impression as it is used in the Newsela article "Flood Myths from around the World" is a first idea about something. In the context of the article, impression refers to the initial understanding or perception that people have about flood myths from different cultures. It represents their first thoughts or notions about these myths before delving deeper into the subject.
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