Rhenium is a rare metallic element with the atomic number 75. It is known for its exceptional hardness and high melting point, making it a popular choice in various industrial and electrical applications. While there aren't many synonyms for the word "rhenium," there are several similar elements, including tungsten and osmium. Other elements in the same group as rhenium include technetium and manganese. Rhenium is also sometimes referred to as perrhenium or perrenium. Despite its rarity, rhenium plays an important role in several industries. It is known to be a useful catalyst in the production of gasoline and is used in the manufacture of jet engine parts.