Yeast infection (also called Candida) - one type of vaginitis, most often caused by the Candida albicans fungus, characterized by itching, burning, or redness of the vaginal area.
Yellow fever - a viral disease that is transmitted by the Aedes aegypti mosquito.
Yin and Yang - Chinese words for complementary and opposite forces that make up the life force (Qi).
Yoga - Indian word for "union." Yoga is a posturing and breathing technique to induce relaxation.