To undo or open a lock or something locked by, for example, turning a key, or selecting a combination.
I unlocked the door and walked in.
To obtain access to something.
I unlocked the dictionary article so I could edit it.
To disclose or reveal previously unknown knowledge.
The discovery of a clue unlocked the mystery.
To be or become unfastened or unrestrained.
The act by which something is unlocked.