If your father is the supreme being, the act of dying is a much bigger deal than rising from the dead. The actual/symbolic death of Jesus for the sins of others is the big event, the rising from the dead was more for show.
Maundy Thursday, Good Friday and Holy Saturday are also known as the Triduum.
The derivation of “Maundy” is unclear - I’ve been taught that it derives from the Latin for “command” or “commandmdent” since it commemorates the Last Supper at which Jesus said “I give you a new commandment; that you love one another as I have loved you.” Others claim that the word refers to begging or the cups held by beggars.
“Shrove” as in Shrove Tuesday is the past tense of the verb “to shrive” which means to confess and do absolution. It’s the day before Ash Wednesday, the beginning of the season of Lent, which continues until Easter.
“Meat” in this context is red meat and, usually, poultry. Fish is the major substitute for protein-rich entrees on “days of abstinence” that are kept meatless – presently the rule, I believe, calls for Ash Wednesday and Good Friday to be kept, with weekdays in Lwent and Fridays as purely optional observances.
Fasting can also mean one “real” meal per day, with “a light collation” in place of the normal second major meal. I.e., if “dinner” is an early-afternoon event, with “supper” following, “Supper” becomes soup-and-sandwich rather than another full meal. Likewise if “dinner” is the evening meal, “lunch” is the light meal. This does not ordinarily prevent meat at the main meal, though some people on strict fasts may do so. While sedentary lifestyles may do this normally, it was an act of self-denial for manual laborers.
And JFTR, if done at all, it’s done to honor God and to strengthen one’s own will. Many good people do not, even in denominations that once called for it.
Skammer is correct that “Maundy” is thought to derive from Mandatum, but the evidence is less than ideal to ‘prove’ this.
Something else about Lent that often gets missed: Sundays don’t count. That is, because each Sunday is a commemoration of the Resurrection, Sundays are Feast days even in Lent. If you’ve embraced a Lenten discipline of fasting - from meat, or chocolate, or caffiene or video games or whatever - you’re supposed to enjoy those things on Sundays. If you count the days between Ash Wednesday and Lent, it’s 46 days: 40 days of fasting and 6 Sundays.
The Wednesday of Holy Week is sometimes referred to as “Spy Wednesday”, as that would have been the day that Judas betrayed Jesus.
Current Roman Catholic rules call for abstinence from meat (meaning the flesh of mammals and birds) on all Fridays during Lent, and abstinence and fasting on Ash Wednesday and Good Friday. The precise definition of “fasting” varies, but in my diocese,
In addition, Catholics are also encouraged to choose something personal to give up during Lent. This is how you’ll sometimes hear “I’m giving up chocolate for Lent”, or alcohol, or whatever.
Per the Catholic Dictionary (CATHOLIC ENCYCLOPEDIA: Good Friday), it’s not clear why it’s called “Good Friday” - some say it’s a modification of “God’s Friday” - in other languages it’s usually called something that doesn’t translate to “Good Friday”
Lenten discipline does not necessarily mean giving something up, either. It could mean taking on a new discipline – for example, a commitment to daily prayer or charity that is beyond what you would normally do.
Lent is generally meant to be a time for penitence, self-examination, and making amends. “Giving something [lawful] up” (candy, say) is considered only one of many forms this could take. Pentitential prayer, trying to right a past misdeed, trying to do supererogatory acts of service/mercy would all qualify too.
Failure to get in the spirit of any of these things would fall under ur not doin it rite, but certainly failure to do one particular form of sacrifice would not be an active sin of commission. Now, IANA theologian, but hmm . . . the intentional omission of making any effort to observe these recommended acts might be a species of or symptom for sloth, which is a [potentially mortal??] sin.