Why do Catholics have the symbols 20+C+M+B+YEAR written in chalk on or above their doors?
The symbols come from a Catholic blessing of the home connected to the Feast of the Epiphany.
Here is what they mean:
20+YEAR = The year of the blessing.
+ = The Cross
C = Caspar
M = Melchior
B = Balthasar
The letters can also stand for “Christus Mansionem Benedicat” which means “May Christ bless this house.”
The chalk symbols are nice reminders that you have asked for a blessing upon your home and all who come in and out of those doors.
Personally, I like that it reminds me to go in and out always searching for the Lord in my life and in the world, just like the magi.