The terms visibility and discernability are also used to refer to the concept of conspicuity. However, their meaning seems to be relatively ambiguous. Luckiesh and Moss (1940), for example, used their own visibility meter to measure the difference in levels of visibility between several degrees of boldness in the typeface Memphis. Their definition of the term visibility (visual sensation) could pertain just as much to legibility as to conspicuity. Naturally, when three concepts are defined, they need to be distinctly different. Terms that are used by some people in reference to one concept, but are used in reference to another concept by others should be avoided. For this reason, the term conspicuity is preferred.

The usability of a typeface, according to the criteria of legibility, readability, and conspicuity, is usually studied with one application in mind. Here, the term application will refer to the use of the printed text. The use of the printed text is defined by its purpose and material; newspapers, signs, textbooks, or advertisements, for instance. As demonstrated earlier in a few examples, the three usability criteria are not equally important for each application. One more example to stress this point. When text is used in logotype, readability is not an issue, since it never concerns more that a few words. In contrast, it may be required of logotype that is highly conspicuous. For textbooks, the opposite is true; text should be highly legible and readable, but need not be made conspicuous. It should be noted, however, that a typeface should not only meet the ergonomics criteria. It should also match the application. Bold ‘typewriter’-letters, for instance, might be suitable for product packaging with regard to the three ergonomics criteria, but might not support the distinctive image required of the product.