Severless is a new paradigm in which the developers do not manage the servers anymore. Developers "just" deploy the codes.
Serverless was pioneered as a Function as a Service (FaaS) with AWS Lambda but now also includes anything that's managed (database, messaging, storage, etc.).
Serverless does not mean there are no servers. It means you just don't manage/provision/see them.
Serverless examples:
- Amazon S3
- Amazon DynamoDB
- Amazon Fargate
- Amazon Lambda