The Collaborative International Dictionary of English v.0.48:

Clause \Clause\, n. [Obs.]
   See Letters clause or Letters close, under Letter.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Clause \Clause\, n. [F. clause, LL. clausa, equiv. to L.
   clausula clause, prop., close of ? rhetorical period, close,
   fr. claudere to shut, to end. See Close.]
   1. A separate portion of a written paper, paragraph, or
      sentence; an article, stipulation, or proviso, in a legal
      document.
      [1913 Webster]

            The usual attestation clause to a will. --Bouvier.
      [1913 Webster]

   2. (Gram.) A subordinate portion or a subdivision of a
      sentence containing a subject and its predicate.
      [1913 Webster]

WordNet (r) 3.0 (2006):

clause
    n 1: (grammar) an expression including a subject and predicate
         but not constituting a complete sentence
    2: a separate section of a legal document (as a statute or
       contract or will) [syn: article, clause]

Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "clause":
   adjectival phrase, article, back matter, bill, book,
   boundary condition, calendar, catch, chapter, column,
   companion bills amendment, condition, construction, donnee,
   dragnet clause, enacting clause, escalator clause, escape clause,
   escape hatch, expression, fascicle, fine print, folio,
   front matter, gathering, given, grounds, headed group,
   hold-up bill, idiom, idiotism, installment, joker, kicker,
   limiting condition, livraison, locution, manner of speaking,
   motion, noun phrase, number, obligation, omnibus bill, page,
   paragraph, parameter, part, passage, peculiar expression, period,
   phrasal idiom, phrase, prerequisite, privileged question,
   provision, provisions, proviso, question, requisite, rider,
   saving clause, section, sentence, serial, set phrase, sheet,
   signature, sine qua non, small print, specification,
   standard phrase, stipulation, string, syntactic structure, term,
   terms, text, turn of expression, turn of phrase, ultimatum, usage,
   utterance, verb complex, verb phrase, verbalism, verse, volume,
   way of speaking, whereas, word-group



The Free On-line Dictionary of Computing (30 December 2018):

clause

   1.  A logical formula in conjunctive normal form,
   which has the schema

    p1 ^ ...^ pm => q1 V ... V qn.

   or, equivalently,

    ~p1 V ... V ~pn V q1 V ... V qn,

   where pi and qi are atoms.

   The operators ~, ^, V, => are connectives, where ~ stands
   for negation, ^ for conjunction, V for disjunction and
   => for implication.

   2.  A part of a sentence (or programming language
   statement) that does not constitute a full sentence, e.g. an
   adjectival clause in human language or a WHERE clause in a
   SQL statement.

   (2004-05-28)


Bouvier's Law Dictionary, Revised 6th Ed (1856):

CLAUSE, contracts. A particular disposition which makes part of a treaty; of
an act of the legislature; of a deed, written agreement, or other written
contract or will. When a clause is obscurely written, it ought to be
construed in such a way as to agree with what precedes and what follows, if
possible. Vide Dig. 50, 17, 77; Construction; Interpretation.