deriv LSK ETT STT aSTA ALPH OLDHOMEPAGE NEWHOMEPAGE
A s;tu स्तु is either the letter s स् or one of the five /tu letters.
So the /stu are —
s स् t त् th थ् d द् dh ध् n न्
These six are also called /dantya or dentals, because the tip of the tongue touches the teeth.