Form Realm / Rūpadhātu
This realm is situated above the Desire Realm.
The celestial beings of this realm still retain the form body (material body).
https://encyclopediaofbuddhism.org/wiki/R%C5%ABpadh%C4%81tu
First Dhyāna Heaven 初禪天
The first of the four dhyāna heavens, corresponding to the first stage of dhyāna meditation.
https://www2.buddhistdoor.net/dictionary/details/%E5%88%9D%E7%A6%AA%E5%A4%A9