The crossword solution for the term POWER SOURCE FOR WATT is STEAM, which is an acronym for 'Science, Technology, Engineering, Arts, and Mathematics'. STEAM is a form of energy that is generated by boiling water, which is then used to power machines and other devices. It is a popular source of energy for many industries, including manufacturing, transportation, and electricity generation. STEAM has been used since the Industrial Revolution to power locomotives, ships, and factories. Today, it is still a major source of energy for many countries around the world.