Caedmon said:
What's the difference between and "fast" and "abstinence"?
Abstinence means no meat. Fasting means one meal a day, plus two smaller meals that together do not equal the main meal, and no eating between meals.
On a day of fast only, meat may be eaten. Since there are currently only two days of fasting, Ash Wednesday and Good Friday, and abstinence is required on both, the distinction becomes less clear.
Caedmon said:
What are the "Ember Days"?
The Ember Days are penitential days which occur four times a year, and they date back to at least 500, but likely apostolic times.
Like many Christian holidays, they developed from pagan rituals which, in this case, honoured the gods of nature. The Romans would pray to these gods in June, September, and December to ask for help with planting and the harvest, since a good crop was vital to one's survival. As the Church so often does, she adopted this practice but sanctified it by making these celebrations times of penance and, of course, directed the prayers to the one true God. A fourth set of Ember days was added later, around March.
The three Ember Days are Wednesday, Friday, and Saturday, which are also the traditional days of fasting in both the Catholic and Orthodox Churches - Wednesday, because Judas betrayed Jesus on that day; Friday, because the crucifixion was on Friday; and Saturday, for the Sabbath.
The Ember Days remain at approximately the beginnings of the seasons of the year, but are tied to the liturgical year - they occur in the First Week of Lent, the Octave of Pentecost, the Third Week in September, and the Third Week of Advent. In the 1917 Code of Canon Law, all three days are days of fast. Friday, like all Fridays, is a day of full abstinence - no meat. Wednesday and Saturday are days of partial abstinence - meat at the main meal only.
Ordinations are performed on the Ember Saturdays, with the main ordination Mass occurring on Ember Saturday in Pentecost, the day before Trinity Sunday. The Mass also contains additional Scripture lessons.
The Ember Days were dropped from the calendar in 1970, but remain on the 1962 calendar. Even though the fast and abstinence is no longer required, extra penance is never a bad thing. Although we don't pray as much these days for the food supply and the seasons, we can still use them as a way of thanking God for the past season and asking His blessing for the coming season.