An Etymological Dictionary of Astronomy and Astrophysics

1. Grammar: A syntactic construction containing a subject and predicate and forming part of a sentence or constituting a whole simple sentence.
   

2. A distinct article or provision in a contract, treaty, will, or other formal or legal written document (Dictionary.com).

Etymology (EN): M.E., from O.Fr. clause, from M.L. clausa “conclusion,” used in the sense of classical L. clausula “the end, a closing, termination,” also “end of a sentence or a legal argument,” from clausa, from p.p. of claudere “to close, to shut, to conclude,” → closure.

Etymology (PE): Band present stem of bastan “to close, to fasten, to bind,” → closure.