根据提供的英文，为每个被高亮表示的单词提供一个定义。
"Charles Dickens wrote many classic novels such as Oliver Twist and A Tale of Two Cities. He was a prolific author, meaning he wrote a lot of books in his lifetime. He was also a social critic, meaning he used his writing to comment on the social issues of his time."
- Classic: A highly-regarded and enduringly popular work of literature or art.
- Prolific: Producing a large volume or quantity; highly productive.
- Social critic: A person who examines and critiques society and culture, with the aim of improving or changing it.