Note: this is an incomplete work in progress. In addition to defining certain terms, I need to list sources referenced in my definitions.
These are terms I regularly use in discussions on Facebook and other online forums. I'm placing it here so that I can refer people to it when necessary.
Apostolic succession: the line of succession leading from the Apostles down to every catholic (note the lower case "c") bishop. To begin at the beginning, God the Father gave authority to Jesus, Jesus gave His authority to the Apostles, and the Apostles appointed bishops as their successors, passing to these bishops their Apostolic authority in matters of faith, morals, and the valid administration of sacraments. Those bishops then ordained other bishops, passing along their Apostolic authority. This line has continued through the ages so that every bishop in every catholic Church has been ordained in this line. Sadly, the same is not true of Protestant communities, many of which don't even claim to have bishops.
bishop: a bishop is a man who was ordained in the line of Apostolic succession and who possesses the fullness of the priesthood to rule a diocese as its chief pastor. The office of bishop is of Divine institution. In the ministerial hierarchy they possess powers superior to those of priests and deacons; in the hierarchy of jurisdiction, by Christ's will, they are appointed for the government of one portion of the faithful of the Church. They are the successors of the Apostles, though they do not possess all the prerogatives of the latter.
catholic (with a lower case "c"): the points of doctrine, theology, and sacramental life on which the Catholic Church, Eastern Orthodox Church, and Oriental Orthodox Church agree. If I use this word at the beginning of a sentence, it will be spelled "c"atholic.
Catholic (with an upper case "C"): refers to the teachings and/or sacramental life of the Catholic Church.
Catholic Church: sometimes mistakenly referred to as the Roman Catholic Church. It is the largest Christian Church in the world, and is headed by the Pope, the bishop of Rome. It is made up of 23 different Churches. Each of the Churches is headed by a bishop (various titles such as Patriarch or Metropolitan may be used instead of bishop, but Patriarchs, etc. are all bishops). The Catholic Churches are:
Albanian Byzantine Catholic Church
Armenian Catholic Church
Belarusian Greek Catholic Church
Bulgarian Greek Catholic Church
Byzantine Church of Croatia, Serbia and Montenegro
Chaldean Catholic Church
Coptic Catholic Church
Ethiopic Catholic Church
Greek Byzantine Catholic Church
Hungarian Greek Catholic Church
Italo-Albanian Catholic Church
Macedonian Greek Catholic Church
Melkite Greek Catholic Church
Roman Catholic Church
Romanian Church United with Rome, Greek-Catholic
Russian Byzantine Catholic Church
Ruthenian Catholic Church
Slovak Greek Catholic Church
Syrian Catholic Church
Syro-Malankara Catholic Church
Ukrainian Greek Catholic Church
celibacy: the state of being unmarried.
celibate: unmarried. If a married couple refrains from sex for a period of time, they are not celibate, they are continent.
chaste: sexually pure.
chastity: sexual purity. All persons, whether single or married, are called by God to be chaste. For single people, chastity involves refraining from lust, pornography, and sexual activity with oneself or other persons, and active service to meet the needs of other people (e.g. encouraging the discouraged, feeding the hungry, clothing the naked, mentoring the young). For married people, chastity involves all the above with the exception that they can focus their sexual desires on and have sexual relations with their spouse.
church (with a lower case "c"): a local body of non-catholic Christians who meet together under self-elected officials (usually called a pastor). Non-catholic churches are not Churches in the proper sense, as they lack Apostolic succession and valid sacraments.
Church (with an upper case "C"): a local body of catholic Christians who are lead by a bishop. Each local body is referred to as a Church, but each one is considered to be the local expression of the True Church established by Christ.
continence: refraining from sexual activity with oneself or other persons.
continent: the state of being sexually inactive.
Roman Catholic Church: the largest of the 23 Catholic Churches. It is headed by the bishop of Rome, who is also the ultimate head of the 22 other Catholic Churches.