urate calculus uric acid calculus. urethral calculus a urinary calculus in the urethra; symptoms vary according to the patient's sex and the site of lodgment. uric acid calculus a hard, yellow or reddish-yellow urinary calculus formed from uric acid.
In some traditions, the first day of Christmas begins on the evening of December 25th with the following day considered the First Day of Christmas (December 26th). In these traditions, the twelve days begin December 26 and include Epiphany on January 6. The origin and counting of the Twelve Days is complicated, and is related to differences in calendars, church traditions, and ways to observe this holy day in various cultures (see Christmas).
Christmas Day in the United States. Many people in the United States celebrate Christmas Day on December 25. The day celebrates Jesus Christ's birth. It is often combined with customs from pre-Christian winter celebrations. Many people erect Christmas trees, decorate their homes, visit family or friends and exchange gifts.