1-2-3 Normal forms

1^st Normal Form – Eliminate Repeating Groups (ERG)
all occurrences of a record type must contain the same number of fields. No sets

2^nd Normal Form – Eliminate Redundant Data (ERD)
violated when a non-key field is a fact about a subset of a key.

3^rd Normal Form – Eliminate Columns Not Dependent on Key (ENDK)
violated when a non-key field is a fact about another non-key field.

All normal forms are additive.

Source