(Canada, historical) Canada Day (before being renamed in 1982) / (New Zealand) A day commemorating the granting of national status to New Zealand.

Columbus Day

(historical) A day on which contributions to some public or private charity or fund are solicited on the street, and tags given to contributors to wear as evidence of their having contributed.

A day which is a term (as for payment of rent), or is a day in a term, as of the sitting of a court.

(US, education) In colleges and universities, a day of the commencement season on which the senior class celebrates the completion of its course by exercises conducted by the members, such as the reading of the class histories and poem, the delivery of the class oration, the planting of the class ivy, etc.

A paid personal day intended to be used due to illness either for recuperation or medical treatment.

A day when one is permitted to not attend work in order to attend to personal matters.

(idiomatic) A difficult period of need, when things do not go right. / Used other than figuratively or idiomatically: see rainy, day.

(childish) A contrived holiday on which everything is done backwards, for example "yes" means "no".

For the period of an entire day, or at least during all the daytime of a day.