What is the difference between view and materialised view?

A view is a simple select statement executed each time user runs query against it

A materialized view is a physical persistent object used for performance improvement of summary data or replication. For summary data, when a user queries data against a table / set of tables using join condition with aggregates and group by and if a corresponding materialized view is already created, query_rewrite is enabled, oracle selects the data from the pre-built materialized view enhancing the performance of select query in data warehouse environment. For replication, materialized view is a replica of target master table for replication to other sites and can be fast refresh (changes since the last refreshed), complete refresh or refresh on demand. Materialized view logs are used to keep the changes since the last refresh.

view does not consume space and materialized view consume space