The term 'Pioneer in Alternating Current' refers to the inventor Nikola Tesla. Tesla was a Serbian-American engineer and physicist who made groundbreaking contributions to the development of electricity and magnetism in the late 19th and early 20th centuries. He is best known for his pioneering work in alternating current (AC) electricity, which revolutionized the way electricity is generated and distributed. Tesla's inventions, patents, and theoretical work formed the basis of modern AC electricity, and contributed to the development of radio, television, and wireless communication.