I came across with this question in a forum.
What do you mean by a Functional Dependency in the process of Normalization ???
A Function Dependency tells you the relationship between two columns in the a table. Functional Dependencies are fundamental to the process of Normalization that describes the relationship between attributes(columns) in a table.
For example, if A and B are attributes of a table, B is functionally dependent on A, if each value of A is associated with exactly one value of B (so, you can say, 'A functionally determines B').
Functional Dependency is related to 2NF, which says "For a relation to be in 2NF its all non-key attributes should be functionally dependent on the entire primary/candidate key."