'Modal' definitions:

Definition of 'modal'

(from WordNet)
adjective
Relating to or constituting the most frequent value in a distribution; "the modal age at which American novelists reach their peak is 30" [syn: modal(a), average]
adjective
Of or relating to a musical mode; especially written in an ecclesiastical mode
adjective
Relating to or expressing the mood of a verb; "modal auxiliary"
noun
An auxiliary verb (such as `can' or `will') that is used to express modality [syn: modal auxiliary verb, modal auxiliary, modal verb, modal]

Definition of 'Modal'

From: GCIDE
  • Modal \Mo"dal\, a. [Cf. F. modal. See Mode.]
  • 1. Of or pertaining to a mode or mood; consisting in mode or form only; relating to form; having the form without the essence or reality. --Glanvill. [1913 Webster]
  • 2. (Logic & Metaph.) Indicating, or pertaining to, some mode of conceiving existence, or of expressing thought, such as the modes of possibility or obligation. [1913 Webster +PJC]
  • 3. (Gram.) Pertaining to or denoting mood. [PJC]

Definition of 'Modal'

From: GCIDE
  • Modal \Mo"dal\(Gram.), n. A modal auxiliary. [PJC]