A modal is a dialog box/popup window that is displayed on top of the current page: Open Modal MODAL definition: 1. a verb, such as "can", "might", and "must", that is used with another verb to express an idea…. Learn more. Modal verbs are auxiliary verbs like can, should, and must that express conditions such as possibility, ability, necessity, and permission. Frequently used modal verbs include… Modal fabric is a semi-synthetic product that comes from beech tree pulp. This textile is primarily used for undergarments, such as pajamas and underwear, but it is useful for some household items like towels or