Bitmap font
A font that will have jagged edges if enlarged, instead of a scalable font where no matter what the size will look just the same. These fonts are comprised of several dots to make a single character.
Above is an example of scalable font vs. a bitmap font. As can be seen in this example as we zoom into the scalable font there is no degradation in the quality. However, it's the complete opposite when we zoom into a bitmap font.
Also see: BDF, Bitmap, Font, Pixelated, Raster, Scalable font, Video definitions