Definition - What does Upavistha mean?
Upavistha is Sanskrit for "seated." Seated yoga postures are typically performed on the floor, supine or in a chair. When upavistha postures are performed on the floor, they are entered from dandasana (staff pose). The hands are used for stability and the yogi engages the core to bring length to the spine.
Yogapedia explains Upavistha
In upavistha postures, the yogi will be seated in a chair or on the floor with the legs extended, bent or crossed, with the upper body engaged and upright. The sit bones are grounded heavily, which provides a stable base from which to perform upavistha postures. The core is engaged with the belly button pulled in toward the spine and the rib cage lifts in order to avoid collapse in the side waist or abdomen. From this starting position, the upper body can fold forward, to the side or even twist; the arms can extend up or reach down for stability; and the yogi can then move into various upavistha asanas.