ख्या

ख्या = ख य आ
hollow connect with
hollow join up to

धातु अर्थ
at प्रकथन = प्र + कथन = प्र + कथ् + ल्युट्
Reed + hand-platform - soft join curve
Reed hand/maneuver raised
reflection hand/maneuver raised

रूढ अर्थ
relate, recount, tell
make known
see, appear

Comments
This धातु does not have a मकार and seems later-day addition. Only interpretation for this and कथ seems plausible in connection to written records. That must be a much later-day phenomenon.
On a second thought, it may not be later day addition. म कार may not be obligatory with महा प्राण