1/3 or may refer to: Dates January 3 (month-day date notation) 1 March (day-month date notation) January of the year 3 AD (month-year date notation) March of the year 1 AD (year-month date notation) Other uses , a fraction of one third, or 0.333333333... in decimal. pre-decimal British sterling currency of 1 shilling and 3 pence 1st Battalion, 3rd Marines, United States infantry battalion One/Three, a 2001 album See also Third (disambiguation)