They discovered a secret passageway.
Meaning: It means they found a hidden way to go from one place to another.
Choice of Words: Discovered means to find or learn something new or unknown. Secret refers to something kept hidden or known only to a few people. Passageway means a narrow path or tunnel used to pass from one place to another. Together, "discovered a secret passageway" means that they found a hidden path that was not known to many.
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Related Expressions