The term 'EXTREMELY BRIGHT' can be summarized by the crossword solution 'NEON'. NEON is a chemical element with the symbol Ne and atomic number 10. It is a noble gas that is colorless, odorless, and tasteless. NEON is used in many applications, including lighting, signs, and lasers. It is also used in television tubes and high-voltage indicators. NEON is known for its bright, glowing color, which is why it is often used to describe something that is extremely bright.