What is the difference between font-weight and font-size?

The correct understanding is that font-weight and font-size serve distinct purposes in typography. Font-weight refers specifically to the thickness or boldness of the text. It allows designers to emphasize specific elements of content by making them appear bolder or lighter, depending on the values used. For example, font-weight can take values such as normal, bold, bolder, or a numerical scale from 100 to 900, where higher values represent thicker text.

On the other hand, font-size determines the size of the text character. It is measured in various units like points, pixels, or ems, and it directly affects how large or small the text appears on the screen. Adjusting the font-size allows for better readability and helps in establishing a visual hierarchy within the design.

This distinction is crucial in web design and graphic design, as it enables designers to create aesthetically pleasing and functional text layouts.