The term 'calendar month' refers to the twelve months of the year, which are typically divided into four seasons. APRIL is a five-letter word and is the fourth month of the year, usually associated with the beginning of spring. October is a seven-letter word and is the tenth month of the year, usually associated with the start of autumn. MAY is a three-letter word and is the fifth month of the year, usually associated with the start of summer. MARCH is a five-letter word and is the third month of the year, usually associated with the start of winter.