The term 'LAST MONTH: ABBR.' can be solved by three different crossword solutions: ULT (3 letters), DEC (3 letters) and SHIP (4 letters). ULT stands for 'ultimo, ' which is a Latin word meaning 'LAST' or 'FINAL.' DEC stands for 'December, ' which is the twelfth and LAST month of the year in the Gregorian calendar. SHIP stands for 'short-hand international pronunciation, ' which is a system of abbreviations used to represent the names of months.