Definition (noun): an auxiliary verb (such as `can’ or `will’) that is used to express modality

Definition (adjective): relating to or constituting the most frequent value in a distribution

Example: the modal age at which American novelists reach their peak is 30

Definition (adjective): of or relating to a musical mode; especially written in an ecclesiastical mode

Definition (adjective): relating to or expressing the mood of a verb

Example: modal auxiliary