Second normal form is a concept in database design that ensures non-redundancy of data in a relational database. Synonyms for second normal form include 2NF or the 2nd normal form. This means that the table must meet the requirements of the first normal form, which all non-key attributes are dependent on the primary key. The second normal form breaks down the same key items on separate tables to reduce data redundancy. It improves on the first normal form by eliminating the potential for redundant data within the same table. By breaking down tables into smaller and simplified units, data management and analysis becomes easier and more efficient.