The term 'most abundant' can be described by the crossword solutions RICHEST, RIFEST, AMPLEST, and MENHADEN. RICHEST is a 7-letter word meaning having a great deal of money or material possessions. RIFEST is a 6-letter word meaning having a large amount of something. AMPLEST is a 7-letter word meaning having a great quantity of something. Finally, MENHADEN is an 8-letter word meaning a type of fish found in abundance in the Atlantic Ocean. All of these words describe having a large quantity of something, which is the definition of the term 'most abundant'.