From The School of Biomedical Sciences Wiki
A condensation reaction is a reaction in which a water molecule is formed, usually in bond making, for example, carbohydrates in making glycosidic bonds.
The production of maltose from two glucose molecules is an example of a condensation reaction-
C6H12O6 + C6H12O6 --> C12H22O11 + H2O
Condensation reactions also occurr in protein synthesis. Where long polymers of amino acids are joined by peptide bonds.