Blessed Saint David's Day (Welsh: Dydd Gŵyl Dewi). Today's the feast day of Saint David, Wales' patron saint, who's said to have died on 1 March 601.
As part of the historic kingdom of England, Wales hasn't a coat of arms but a badge, and is unrepresented in the Royal Arms of the United Kingdom. It's badge is the Royal Badge of the National Assembly of Wales. It was designed in 2008.
At its heart is an escutcheon (in heraldry, a shield or emblem bearing a coat of arms) with the arms of Welsh prince Llywelyn the Great (c. 1172 – 1240), Wales' de facto ruler for a time.
The description of a heraldic display is called a blazon and follows a traditional style, the Anglo-Norman terminology of which reflects the Norman-French origins of English heraldry; e.g., Or for gold, gules for red, passant, which in modern French means busy but in heraldry means charging, which is indicated by showing a heraldic beast's right forepaw raised, guardant meaning face turned toward the viewer (from the Old French guarder, to protect or to look at), et cetera.
The blazon of Wales' royal arms is:
Within a circular riband vert fimbriated Or bearing the motto Pleidiol Wyf i'm Gwlad (Welsh for "I am true to my country") in letters the same and ensigned with a representation of the Crown proper, an escutcheon quarterly Or and gules four lions passant guardant counterchanged armed and langued azure, encircled by a wreath alternating of leek, thistle, clover, leek and rose.