1. An iron deficiency anemia in young women; characterized by weakness and menstrual disturbances and a green color of the skin; green-sickness, a rare form of anemia in humans.
2. A yellowing or whitening of a plant's leaves and stems caused by a lack of chlorophyll.
3. An abnormally yellow color of plant tissues, resulting from partial failure to develop chlorophyll, caused by a nutrient deficiency or the activities of a pathogen.
4. An abnormal condition characterized by the absence of green pigments in plants, because of a lack of light, or as a result of magnesium-deficiency or iron-deficiency, or to genetic factors inhibiting chlorophyll synthesis.