In gardening, the term “dormancy” refers to a perennial plant’s state of temporary metabolic inactivity or minimal activity. Plumeria generally goes dormant in response to adverse growing conditions, such as during the cold winter months when daylight is shortest and temps are below 50 degrees. Dormancy can also happen during a period of intense heat or drought. It’s important to remember that plants don’t die at this time, but are simply in suspended animation. While the leaves may fall off and above-ground foliage may look like it just a dead stick, life still lurks in the roots and core of the plumeria. The term “dormancy” isn’t often used to describe annual plants with a life cycle of a single growing season. Their biology does not include the mechanism for going dormant.

During dormancy, plumeria stop or slow down growth to conserve energy until better cultural conditions present themselves. This happens naturally as seasons and weather changes.

Plumeria Dormancy definition:

A period in which a plumeria does not grow, awaiting  necessary  environmental conditions such as temperature, moisture, nutrient  availability, etc.
A state of quiet, but temporary inaction. 
Quiet and inactive rest fullness. A state when organisms are in unfavorable conditions, and slow down their metabolic processes to a minimum to retain resources until conditions are more favorable. Plants may do this when their is a lack of water, while animals, such as the garden dormouse, hibernate, which is also a form of dormancy.