What is the primary characteristic of serif fonts?

The primary characteristic of serif fonts is indeed the presence of "wings" or small decorative strokes at the ends of the letters. These features, known as serifs, help to create a more traditional and formal appearance, which can improve readability in print. The distinct strokes can lead the eye along the lines of text, making it easier to read in longer passages, especially in printed materials such as books and newspapers.

In contrast, sans-serif fonts, which are often used for digital media and minimalist designs, lack these embellishments, leading to a cleaner and more modern look. Uniform stroke width and other characteristics might apply to various font types but do not specifically define serif fonts, nor are serif fonts limited to digital media; they can be effectively used in both print and digital formats.