An entity can be defined as a person, place or thing.

An attribute is a property of an entity. An attribute of a person could be their name.

A relationship is an association between two entities. For example there is a relationship between a student and the course they have taken.

An attribute (B) is functionally dependent on another attribute (A) if a value for attribute A determines a single value for attribute B at any one time. For example a name is frequently functionally dependent on an ID.

A primary key has all other attributes in the table functionally dependent on it.

A non-key attribute is an attribute that is not part of the primary key.

First normal form: A relation is in first normal for (1NF) if it does not contain repeating groups.

Second normal form: A relation is in second normal form (2NF) if it is in first normal form and no non-key attribute is dependent on only a portion of the primary key.

Third normal form: A relation is in third normal form (3NF) if it is in second normal form and if the only determinants it contains are candidate keys.

Source is Database Systems Management and Design by Pratt and Adamski