The term 'PEA-SOUP' is composed of two words: 'FOG' and 'SPLIT'. 'FOG' is a three-letter word that refers to a thick cloud of tiny water droplets suspended in the air near the ground, which obscures visibility. 'SPLIT' is a five-letter word that means to divide or separate into two or more parts. Together, these two words form the term 'PEA-SOUP', which is a type of thick soup made from dried peas, onions, celery, and other vegetables.