ECHO is a playable word

echo Scrabble® Dictionary

noun
pl. echos or echoes
a repetition of sound by reflection of sound waves
verb
echoed, echoing, echoes
to produce an echo
10 Playable Words can be made from "ECHO"
   2-Letter Words (5 found)
   3-Letter Words (3 found)
   4-Letter Words (2 found)