1. An abnormal fear of rain: Because her parents died in a deluge and flooding when she was a child, Jane developed pluviophobia and avoided going outside even when it was just sprinkling.
2. In biology, life-threatening conditions for certain species of plants and other life forms when there are large amounts of rainfall: Valerie received orchids and a book about them as birthday presents and she read that orchids were affected by pluviophobia requiring very little water, plenty of light from outside, but no direct sunlight, and should exist at room temperature.