1. An abnormal fear of dryness or of dry places: Deserts are one example why people have a xerophobia because they might have a horror of not getting enough water to survive!

In biology, a xerophobia is an aversion to arid habitats by animals, or an inability of certain plants to survive in such moistureless locations.

2. The inhibition of salivary flow resulting in a dry mouth: Such xerophobias are caused by emotional conditions, such as fear, anger, or excessive excitement.