It is indeed
https://www.scales-chords.com/findnotes_en.php?n1=E&n2=&n3=&n4=A&n5=D&n6=G
You can see how a single chord even with three notes doesn't define the chord as clearly as some people here would have you believe, just that one example of eadg throws up multiple possibilities, of course if it was written down then you'd have the key signature and also no need to define anything because the notation would tell you the key and which notes to play, even a two note chord.