1) a gathering of citizens called out from their homes into some public place, an assembly
1a) an assembly of the people convened at the public place of the council for the purpose of deliberating
1b) the assembly of the Israelites
1c) any gathering or throng of men assembled by chance, tumultuously
1d) in a Christian sense
1d1) an assembly of Christians gathered for worship in a religious meeting
1d2) a company of Christian, or of those who, hoping for eternal salvation through Jesus Christ, observe their own religious rites, hold their own religious meetings, and manage their own affairs, according to regulations prescribed for the body for order's sake
1d3) those who anywhere, in a city, village, constitute such a company and are united into one body
1d4) the whole body of Christians scattered throughout the earth
1d5) the assembly of faithful Christians already dead and received into heaven
Part of Speech: noun feminine
Citing in TDNT: 3:501, 394
From a compound of G1537 and a derivative of G2564; a calling out, that is, (concretely) a popular meeting, especially a religious congregation (Jewish synagogue, or Christian community of members on earth or saints in heaven or both): - assembly, church.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root ἐκκλησία; click on the second column to search for that grammatical form of the root ἐκκλησία; click on the third column to search for that word and grammatical form; click on the total to search for the root ἐκκλησία.