In the Liturgical year, the first day of Lent. The Jewish and Christian scriptures mention prayer and repentence while fasting and being covered in ash and sackcloth; so, the Catholics started marking the beginning of Lent by putting ash on their foreheads. It's a tradition that extends back about 1,000 years. The ashes are made from the burnt palm branches used on Palm Sunday of the previous year.
Although it's not a holiday of obligation, Catholics flock to mass on Ash Wednesday to get their ashes and begin lent. Although many prayers are now used when the ashes are being administered, the old-time prayer everyone knows is:

Remember Man that you are Dust
And unto Dust you shall return.
Okay, so I went to the Gay Student Union meeting one night, and some retard told me I had dirt on my head. I told him, "It's Ash Wednesday... you're SUPPOSED to have dirt on your head, duh!" But some people just don't know what's cool.
by Van Pierce March 6, 2004
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The day 40 days before Good Friday in the Catholic/Christian Calendar. Marks the beginning of Lent.
I went to church on Ash Wednsday
by John the Baptist March 16, 2004
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Actually a miss pronunciation of "Hash Wednesday", a day of the week following Mescaline Monday and Trippin' Tuesday and preceeding THC Thursday and Freebase Friday.
Steve Albert and a few other guys from my TV class came over to jam and do some bong hits on Hash Wednesday.
by Fast Bobby March 2, 2004
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Fourty days before Easter and the beginning of Lent when all the Catholics walk around with smudges on their foreheads and begin a fast from some vice or food or luxury and go around complaining to their friends about how great a sacrifice they are making when they are asked about the black smudge on their forehead.

It is supposed to be for the purpose of remembering Christ's sacrifice on the cross. So that everytime you crave the thing you are giving up you will remember the crucifixion and be thankfull or do something good for people.
Dude1:Dude, you have something on your forehead.

Catholic Dude:It's ashes, Man, it's ash wednesday. Dude, i gave up sex for lent.

Dude1: Man, you haven't gotten laid in months anyway, Dude.
by cass March 10, 2004
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ash wednesday is a catholic holiday that reminds catholics that they started out as ashes and will eventually become ashes again (in death). It is also a time of repentance of sin. During ash wednesday catholics attend mass (church) and the preist puts on teir forehead, a cross of ashes . the ashes come from the palms burnt from palm sunday of that year.
by allie February 29, 2004
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