Taper
The scheduled wind-down over the final days before harvest, bringing CO₂, canopy temperature and humidity down together rather than one at a time.
The taper is counted backward from harvest rather than forward from the flip, because it is defined by the end date and cycle length varies by cultivar. A 10 day taper on a 9 week plant begins partway through week 8.
Its parts move together on purpose. The warm canopy is only defensible while enrichment is suppressing photorespiration, so the heat comes down with the gas. The night dew point comes down with the room, which is what holds relative humidity flat instead of letting it climb as the room cools.