Strong's #3304: menounge (pronounced men-oon'-geh)
 from 3203 and 3767 and 1065; so then at least:--nay but, yea doubtless (rather, verily).
Thayer's Greek Lexicon:
 ͂ 
 
  menounge 
 
 1) nay surely, nay rather
 
  Part of Speech: particle
Relation: from G3203 and G3767 and G1065
 
Usage:
This word is used 4 times:
Luke 11:28: "But he said,  Yea rather, blessed are they that hear the word"
Romans 9:20: " Nay but, O man, who art thou that repliest against God?"
Romans 10:18: "I say, Have they not heard?  Yes verily, their sound went into"
Philippians 3:8: "Yea  doubtless, and I count all things but loss for"