A "serif" is a small decorative line or stroke that is added to the ends of a letter's main strokes in certain typefaces. Fonts that include serifs are often referred to as serif fonts. These features can enhance readability and give a more traditional or formal appearance to the text. Common examples of serif fonts include Times New Roman and Georgia. Serif fonts are frequently used in printed materials, such as books and newspapers, because they can help guide the reader's eye along the lines of text.