To write "Teachers Day," the most common and formally accepted way is to use the plural possessive form with an apostrophe after the "s," as in "Teachers' Day." This indicates the day belongs to all teachers collectively. It is important to capitalize both words as it is a proper noun for the special day. For example, "Teachers’ Day is celebrated on 5th September every year." Some style guides like the Chicago Manual of Style and APA use the apostrophe, while AP style prefers to omit it as a descriptive term ("Teachers Day"). However, the possessive form with apostrophe after "s" is widely accepted and used officially (e.g., "World Teachers’ Day").
When writing about Teachers' Day, it is customary to capitalize both words and use the apostrophe after the "s" unless following a particular style guide that recommends otherwise.
