What is conjunctivitis commonly referred to as?

Conjunctivitis is commonly referred to as "pink eye" because it is characterized by inflammation of the conjunctiva, which can cause redness and swelling of the eye, leading to a pinkish appearance. This condition can result from various factors, including infections, allergies, and irritants. The term "pink eye" is widely recognized and used in both medical and common vernacular to describe the symptoms and visibility of the condition.

The other terms listed do not accurately describe conjunctivitis. The flu refers to an influenza virus infection, a respiratory illness. A dust allergy involves an allergic reaction to dust, which typically affects the respiratory system rather than the eyes. Seasonal fever is not a medically recognized term and may refer to allergies triggered by seasonal changes, which again is distinct from the inflammation seen in conjunctivitis.