Peat sources are natural deposits of organic matter that accumulate over time in wetlands. The four crossword solutions for the term PEAT SOURCE are MIRE (4 letters), MOSS (4 letters), FEN (3 letters), BOG (3 letters), and SPHNUM (6 letters). A MIRE is a type of wetland with a deep accumulation of peat, while MOSS is a type of vegetation that grows in wet environments. A FEN is a type of wetland with a shallow accumulation of peat, and a BOG is a type of wetland with a deep accumulation of peat. Sphagnum is a type of MOSS that is commonly found in bogs and is an important source of peat.