The process of combining two sugars and losing a water molecule is called dehydration synthesis.

Here's a breakdown:

* Dehydration: This refers to the removal of water.

* Synthesis: This means building a larger molecule from smaller ones.

In dehydration synthesis, a hydroxyl group (-OH) from one sugar molecule and a hydrogen atom (-H) from the other sugar molecule are removed, forming a water molecule (H2O). The remaining portions of the two sugars then join together to form a larger disaccharide molecule.

This process is crucial for building complex carbohydrates like starch and cellulose.