Second Normal Form (2NF) is a database design principle that aims to reduce redundancy and improve data integrity. A table is in 2NF if it is already in First Normal Form (1NF) and all non-key attributes are fully functionally dependent on the entire primary key. This means that no non-key attribute should depend only on a part of a composite primary key. To achieve 2NF, you may need to split a table into smaller tables. For example, if you have a table with student information and course details, and the course information depends only on the course ID, you should create a separate table for courses to eliminate partial dependencies.