megas (Greek #3173)
big (literally or figuratively, in a very wide application)
KJV usage: (+ fear) exceedingly, great(-est), high, large, loud, mighty, + (be) sore (afraid), strong, X to years.
Pronounce: meg'-as
Origin: (including the prolonged forms, feminine μεγάλη, plural μεγάλοι, etc.; compare also 3176, 3187)
dunamis (Greek #1411)
force (literally or figuratively); specially, miraculous power (usually by implication, a miracle itself)
KJV usage: ability, abundance, meaning, might(-ily, -y, -y deed), (worker of) miracle(-s), power, strength, violence, mighty (wonderful) work.
Pronounce: doo'-nam-is