The query "when is" is incomplete and ambiguous; it could refer to a question asking for the timing of an event or occurrence. To provide a meaningful response, more context or a complete question is needed. However, broadly, "when" is a question word used to ask about the time of an event or action, e.g., "When is the meeting?" or "When is the holiday?" It is also used as a conjunction to link clauses referring to time. If the intent is to inquire about specific dates or events, please specify the event or context (e.g., "when is Christmas?", "when is the next eclipse?"). For general understanding, "when" is defined as "at what time" or "at or during which time" according to dictionaries. If the user is asking about dates or holidays, calendars and event listings could be provided upon specifying the context.
