difference between a User and a Schema in Oracle?

From Ask Tom

You should consider a schema to be the user account and collection of all objects therein as a schema for all intents and purposes.

SCOTT is a schema that includes the EMP, DEPT and BONUS tables with various grants, and other stuff.

SYS is a schema that includes tons of tables, views, grants, etc etc etc.

SYSTEM is a schema…..

Technically — A schema is the set of metadata (data dictionary) used by the database, typically generated using DDL. A schema defines attributes of the database, such as tables, columns, and properties. A database schema is a description of the data in a database.

http://stackoverflow.com/questions/880230/difference-between-a-user-and-a-schema-in-oracle