ज्ञ

ज्ञ = ज ञ अ
open/widen surface (net/hyde/cloth) here
wide surface here - plains, earth
literal and metaphorical rabbit hole, and hence knowledge and knowledgeable
place (this meaning is lost in Sanskrit but persists in Vietnamese)

ज = wide/spread/ yawn
ञ = surface
अ = here

commentary
refer to अञ्ज् it also means ज्ञ. Both refer to the same act.
The following words are derived from ज्ञ
geo
geology
geography
geometry
Gypsum
Egypt
Gypsy
Gyros