I’ve also heard it called Half Angel (without necessarily explaining full Angel…), for example here.
For this move, you should have one hand and the top of the opposite leg on the bottom bar of the hoop. The other hand and leg are extended away and your body is facing downwards. A similar move where your body is facing upwards is sometimes called reverse angel (you can move into this by just turning in angel, like here). I’ve occasionally also seen reverse angel name used for a simiar move where your hand and same leg are on the hoop.
You can enter this pose from Mermaid by taking your top leg off, as shown below. You can exit through hocks, for example.