Heating a solution of alcohol and water, then collecting the alcohol vapors and condensing them into a liquid with higher alcohol content, is called

Distillation.

Explanation:

If we are heating a mixture of two miscible liquids and collecting the vapors it means we are separating the two mixtures from each other based on their boiling point differences.

This technique of separation of two liquids based on the difference in boiling point is known as Distillation.

Alcohol will evaporate easily as compared to water as water has stronger influence of hydrogen bond making the inter-molecular forces stronger.