Definition - What does Hiranyagarbha mean?
Hiranyagarbha is a Sanskrit term that translates to “golden embryo,” “golden womb” or “golden egg.” It is derived from the root words hiranya, meaning “golden” or “wealth,” and garbha, meaning “womb,” “germ/seed" or “essence.” It is also the name of the founder of the yoga tradition -- predating even Patanjali, who authored the Yoga Sutras. Whether Hiranyagarbha was human or a deity is not established, but the name first appears prominently as a form of the sun god.
The pre-Pantanjali yoga system is sometimes referred to as hiranyagarbha yoga darshana (yoga system of philosophy).
Yogapedia explains Hiranyagarbha
Hiranyagarbha is mentioned in ancient literature and verse. The "Rig Veda," for example, contains a hymn to Hiranyagarbha that Hindus still chant in their daily rituals, in which he is referred to as the Supreme Being. The epic narrative, "Mahabharata," cites Hiranyagarbha as the one who is glorified in Vedic verses and taught in yoga literature. The Upanishads call him the Supreme Existence, or Brahman. In this regard, Hiranyagarbha is also a name for Brahma in classical Puranic Hinduism because he was born from a golden egg.
While Hiranyagarbha appears most often as a deity or deity in human form, it is possible that a human teacher with the name once existed. Rishi Vashishtha, one of the most prominent Vedic sage-seers, is said to be the main disciple of Hiranyagarbha.