Database Normalization is a technique of organizing the data in the database. Normalize the redundancy with Insertion, Update and Deletion Anamolies of the data into database. It is a multi- step process in which we gave data in tubler form and than removing duplicated data from the relation tables. 

Third normal form(3NF) is used in database normalization as a normal form.its states in that table is in 3NF. The given relation R(table)is in 2NF. Every non-prime attribute is non-transitively dependent on every key in R. 

Example : 

CREATE TABLE CUSTOMERS( 
   CUST_ID       INT              NOT NULL,

   CUST_NAME     VARCHAR (20)      NOT NULL,

   DOB           DATE,

   STREET        VARCHAR(200),

   CITY          VARCHAR(100),

   STATE         VARCHAR(100),

   ZIP           VARCHAR(12),

   EMAIL_ID      VARCHAR(256),

   PRIMARY KEY (CUST_ID)

);

in transitive dependency with the third normal form, all you need to do is to move the Street, City and the State fields into their own table. 

CREATE TABLE ADDRESS( 
   ZIP           VARCHAR(12),

   STREET        VARCHAR(200),

   CITY          VARCHAR(100),

   STATE         VARCHAR(100),

   PRIMARY KEY (ZIP)

);