“Gacch” (गच्छ) is a Jain term, mainly used in Śvetāmbara Mūrtipujak tradition. It means a monastic order / subgroup – a line of sadhus‑sādhvīs connected by one ācārya‑paramparā and certain maryādā (discipline style).

Famous Śvetāmbara Mūrtipujak gacchas are for example:

• Kharatara Gacch
• Tapa Gacch
• Anchal (Āñcal) Gacch
• Tristutik / Brihad etc.

About “Gyan Gacch” specifically:

• In the main, well‑known Śvetāmbara or Digambar lists, there is no big, classical gacch normally known by the name “Gyan Gacch.”
• It is very likely a local sangh / trust / institution’s name, or a small branch / group using “Gyan” as an honorific title, not a separate historic gacch like Tapa or Kharatara.

So:

• Yes, I know what gacch is and how gacchas work in Jainism.
• But I am not aware of any major traditional monastic order officially called “Gyan Gacch” in the standard Jain histories; it is probably a local or recent name.