noon; midday; the time of day when the sun is at its zenith

Used between clauses to show a logical result or consequence, often translated as "then", "in that case", or "consequently".

(bound form) literary term for the sun declining to the west or the afternoon period; specifically used in the context of the sun passing its zenith as in the phrase 日中则昃 rì​zhōng​zé​zè