ZooKeeper is not a general-purpose database. I have heard of anyone using it as one, either.
> What is your definition of NoSQL?
I don't have one, and I think the term isn't terribly useful. But the whole idea of NoSQL started as an attempt to break free of the relational aspect of SQL, because things like joins, strict schemas, foreign keys, and normalization were perceived as getting in the way of distribution. ArangoDB supports joins (but not foreign keys, because it's schemaless) and an SQL-like query language, which makes it a lot closer to an SQL database than something like Redis or Cassandra.
> What is your definition of NoSQL?
I don't have one, and I think the term isn't terribly useful. But the whole idea of NoSQL started as an attempt to break free of the relational aspect of SQL, because things like joins, strict schemas, foreign keys, and normalization were perceived as getting in the way of distribution. ArangoDB supports joins (but not foreign keys, because it's schemaless) and an SQL-like query language, which makes it a lot closer to an SQL database than something like Redis or Cassandra.