Also known as monogram logos, lettermarks use the initials or acronyms of the brand. These letters are usually stylized into a standardized format that is eye catching or memorable in some way. These type of logos are typically short (as is standard with acronyms) and as such, the chosen font is of utmost importance. Simplicity and readability is key. An example of a brand that uses a lettermark is NASA (National Aeronautic and Space Administration) Their name is certainly a mouthful and shorting it to NASA as well as their use of a stylized font has increased their public accessibility.