Answer: occasion

AnswerCrossword Clue
OCCASIONBirthday, e.g.
occasionReason; cause
occasionA suitable or opportune time for doing something
occasionto cause (to bring about)
occasionA special or noteworthy event, ceremony, or celebration
occasionA particular time or instance of an event
OCCASIONReason to have a party
OCCASIONCause
OCCASIONBig event
OCCASIONWedding or birthday, e.g.
OCCASIONSpecial event
OCCASIONReason to celebrate
OCCASIONSpecial time
OCCASIONEvent
OCCASIONHappening.
OCCASIONOpportunity.
OCCASIONParticular time
OCCASIONTime to celebrate
OCCASIONHappening
OCCASIONBirthday, say