Strong's #4867: sunathroizo (pronounced soon-ath-royd'-zo)
 from 4862 and athroizo (to hoard); to convene:--call (gather) together.
Thayer's Greek Lexicon:
 ́ 
 
  sunathroizō 
 
 1) to gather together with others
 2) to assemble
 3) to be gathered together, i.e. to come together
 
  Part of Speech: verb
Relation: from G4862 and athroizo (to hoard)
 
Usage:
This word is used 3 times:
Luke 24:33: "found the eleven  gathered together, and them that were with them,"
Acts 12:12: "where many were  gathered together praying."
Acts 19:25: "Whom  he called together with the workmen of like occupation, and said,"