Final answer:
Plaintext is associated with data encryption and refers to unencrypted, readable data that can be directly understood by users before it is encrypted into ciphertext.
Step-by-step explanation:
The term plaintext is associated with data encryption. In the context of encryption, plaintext refers to any text or data that is readable and not encrypted, meaning it is in a format that can be directly understood by the user without requiring decryption. When data is secured through encryption, the plaintext is transformed into ciphertext, which obscures the data for unauthorized users. To regain the original readable format, an authorized user must decrypt the ciphertext using an encryption key. This process is fundamental to securing data in various applications such as secure communications, confidential documents, and secure data transmission.