Definitions of the Gorakṣanātha’s name sometimes contain many references to its etymology, especially to the term “Go“. I want to share one of them, perhaps later I will give other quotes. Here is one of Yaskacharya’s works with my comments:
सुषुम्णः सूर्यरश्मिश्चन्द्रमा गन्धर्वः। (Yajurveda, śloka 18.40)
The Moon is a Gandharva, representing the rays of the auspicious (suṣumṇā) Sun (Sūrya).
इत्यपि निगमो भवति । सोऽपि गौरुच्यते।
Following is also in the Vedic scriptures: It (light) is also called “Go”.
“अत्राह गोरमन्वत” इति तद् उपरिष्टाद् व्याख्यास्यामः।
This will also be discussed further “atrāha goramanvata” (quote from Rigveda 1.84.15)
सर्वेऽपि रश्मयः गावः उच्यन्ते।
Also, all rays of light are called “Go”.
And so, in etymology from the Vedas we get that “Go” or “Gau” is light or rays of light, and here there is a reference to the Yajurveda, where mentioned the name of suṣumṇā, which in Nāth–yoga and Tantrism is used as the name of the main channel in our body. I believe that the mention of Sūrya and Chandra is not accidental here, which in Nāth–yoga are further used as images of the iḍa and piṅgala channels surrounding the suṣumṇā channel.
The complete śloka of the Rigveda quoted by Yaska as following:
अत्राह॒ गोर॑मन्वत॒ नाम॒ त्वष्टु॑रपी॒च्य॑म्।
इ॒त्था च॒न्द्रम॑सो गृ॒हे ॥
In this world, they (ṛṣi) perceived the beautiful rays of the Sun in this way in the house of the Moon.
In that way, we are talking here about a certain concentration of light, accumulation between the Sun and the Moon, which are called “Go”. They are collected, that indicates on their protection (rakṣaṇa), i.e. what we know as “tapasya”, the generation of internal light or fire within. This reflects the essence of the practices of Gorakṣanātha. The Nāthas also associate Patra Devatā (Deity in the form of a vessel) with him. For example, we find similar ideas in Tantrism or even Kabbalah, about receiving or accumulating light in oneself (in the body). Light is also a reflection, an “imprint”, called mudrā. Thus, the earrings of the Nāthas, threaded into the space of the ears, are also symbols of the Sun and Moon in space, they are also called “mudrā”. This term is from the root “mud” – means “mixing”, the merging of higher consciousness and matter or spirit, which gives life and form to matter. The form is then given a meaning or mission in this world and becomes a form of life. Thus, Gorakṣanātha is a symbol of life, as opposed to death (mṛita), he is a symbol of immortality “amṛta”, the basis of which lies in the pure light of spirit (Ātman).
From the above it follows that Gorakṣanātha’s practices are aimed at the central channel (suṣumṇā) in our body, this is the gateway to the world of spirit and immortality, to the collecting together (samādhi) of consciousness and pranas.