Letters that make serial operation
s, a, o, e, l, n, p, r, t, i are letters that make 'serial operation'
Words within serial operation
ER, opera, Opera, rial, pe, ti, ERA, ration, at, ratio, SE, RI, on, serial, operation, rat, RA, AL, IA, Io, ion, Ra, Al, At, Er, Se, Ti, era are words within 'serial operation'