Ecclesia (or Ekklesia) in Christian theology means both: a particular body of faithful people, and the whole body of the faithful. Latin ecclesia, from Greek ekklesia had an original meaning of "assembly, congregation, council", literally "convocation".
If one speaks of the whole body of Christian faithful, then there are included not only the members of the Church who are alive on earth but all who were members of the church before. Some churches therefore describe the Church as being composed of the Church Militant (Christians on Earth) and the Church Triumphant (Christians in Heaven). In Catholic theology, there is also the Church Suffering (Christians still in purgatory).
The Christian family, the most basic unit of Church life, is sometimes called the domestic Church
Finally, 'The Church' may sometimes be used, especially in Catholic theology, to speak of those who exercise the office of teaching and ruling the faithful, the Ecclesia Docens, or again (more rarely) the governed as distinguished from their pastors, the Ecclesia Discens.