Large Print is one of the four accessible formats that may be used by people with a print disability.
According to the National Center on Accessible Educational Materials 
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The large print format provides the same content as standard print, only in larger font to help those with visual impairments read more easily. Large print is generally defined as print that is larger than print sizes of 8 to 12 points commonly used by the general population. Some use a guideline for defining large print as 18 point or larger. Large print refers to hard copy paper and may be printed on pages that are the same size as a standard textbook page or on pages of a larger size. When textbooks are printed on the larger sized paper, the books can be heavy and bulky. However, many current large print textbooks are produced in a page size more typical for all textbooks; so depending on the number of pages, they may be more portable and student “friendly.”
When seeking to determine if large print is the most appropriate method for a student to read, the team considers all aspects of providing access to textbooks and other instructional materials. For example, in the early grades, print educational materials are generally provided in a larger print size, which may be sufficient for the student’s access. As a student progresses through the grades, ongoing monitoring of print characteristics and reading efficiency needs to occur to ensure appropriate use of large print materials. Other factors affecting visual access need to be considered for a student using large print. For example, variables such as contrast, clutter, and spacing in print presentation of text may affect a student’s ability to read efficiently.
In today’s learning environments, students are reading printed text on paper and displayed text on computer screens and a variety of other electronic tools and devices. Some people refer to text on paper as large print and text displayed on electronic tools as large text. Students requiring large print or enlarged text should have the opportunity to become proficient in reading textbooks and learning materials in a variety of media and output features.