Literally speaking, "NoSQL" as much for databases as "NoHTTP" means for application protocols. It says literally nothing other than it's not something else.

It could be key-value database or it could be a graph database. It could have a schema or it could be schemaless. It could support one index or it could support multiple. It could have a permissions system or it could be single-user. It could have a server process or it could be embedded.

The author is thinking of the MongoDB and CouchDB variety.