A long journey is a lengthy and often arduous undertaking, usually involving travel. The four crossword solutions for this term are TREK (4 letters), TOUR (4 letters), VOYAGE (6 letters), and ODYSSEY (7 letters). TREK is a long and difficult journey, usually on foot. TOUR is a journey for pleasure or education, often in a group. VOYAGE is a long journey, especially by sea or in space. ODYSSEY is an extended adventurous journey, especially one filled with notable experiences.