Wordnet 3.0
NOUN (1)
1. 
 the activity of making clear or converting from code into plain text; 
- Example: "a secret key or password is required for decryption"[syn: decoding, decryption, decipherment]
WordNet (r) 3.0 (2006):
decryption
    n 1: the activity of making clear or converting from code into
         plain text; "a secret key or password is required for
         decryption" [syn: decoding, decryption, decipherment]
The Free On-line Dictionary of Computing (30 December 2018):
decryption
    Any procedure used in cryptography to convert
   ciphertext (encrypted data) into plaintext.
   (1995-05-10)