MongoDB Documentation, Release 3.0.4 Jargon and Common Terms Pre- ferred Term Concept Dispreferred Alternatives Notes docu- ment A single, top-level object/record in a MongoDB collection. record, object, row Prefer document over object because of concerns about cross-driver language handling of objects. Reserve record for “allocation” of storage. Avoid “row,” as possible. database A group of collections. Refers to a group of data files. This is the “logical” sense of the term “database.” Avoid genericizing “database.” Avoid using database to refer to a server process or a data set. This applies both to the datastoring contexts as well as other (related) operational contexts (command context, authentication/authorization context.) in- stance A daemon process. (e.g. mongos or mongod ) process (acceptable sometimes), node (never acceptable), server. Avoid using instance, unless it modifies something specifically. Having a descriptor for a process/instance makes it possible to avoid needing to make mongod or mongos plural. Server and node are both vague and contextually difficult to disambiguate with regards to application servers, and underlying hardware. field name The identifier of a value in a document. key, column Avoid introducing unrelated terms for a single field. In the documentation we’ve rarely had to discuss the identifier of a field, so the extra word here isn’t burdensome. field /v alue The name/value pair that describes a unit of data in MongoDB. key, slot, attribute Use to emphasize the difference between the name of a field and its value For example, “_id” is the field and the default value is an ObjectId. value The data content of a field. data Mon- goDB A group of processes, or deployment that implement the MongoDB interface. mongo, mongodb, cluster Stylistic preference, mostly. In some cases it’s useful to be able to refer generically to instances (that may be either mongod or mongos .) em- bed- ded docu- ment An embedded or nested document within a document or an array. embedded document, nested document map- reduce An operation performed by the mapReduce command. mapReduce, map reduce, map/reduce Avoid confusion with the command, shell helper, and driver interfaces. Makes it possible to discuss the operation generally. clus- ter A sharded cluster. grid, shard cluster, set, deployment Cluster is a great word for a group of processes; however, it’s important to avoid letting the term become generic. Do not use for any group of MongoDB processes or deployments. sharded clus- ter A sharded cluster . shard cluster, cluster, sharded system replica set A deployment of replicating mongod programs that provide redundancy and automatic failover. set, replication deployment de- ploy- ment A group of MongoDB processes, or a standalone mongod instance. cluster, system Typically in the form MongoDB deployment. Includes standalones, replica sets and sharded clusters. 13.5. Contribute to the Documentation 935