Honorific noun used to refer to someone's departure or setting out, often in formal or respectful contexts.
Honorific noun for the act of standing, typically used in formal or respectful situations.
The president's departure is at 2 p.m.
We are waiting for the honored guests to stand.
Noun formed by adding the honorific prefix お to the continuative form (連用形) of the verb 立つ (たつ, 'to stand'). The meaning extends to 'departure' from the idea of standing up to leave.