श्रत्

श्रत् = श ऋ त
stake/javeline superior + त as “way of” indicator.
stake superior bamboo
stake superior + umbi
Long/Erect superior +way of
Long/Erect superior bamboo

possible but seems unulikely -
श्रत् = श र त or श ऋ त
stake flow float

रूढ अर्थ - all concurring with “way of erect/long superior”
Reverence
belief
True, faithful
credo

commentary
ऋ is not a संयुक्त अक्षर of र and उ. It is a स्वर on its own right. Hence when ability to speak oeiginal ऋ was lost original word could have becomes श्रत् as well as श्रुत