An Etymological Dictionary of Astronomy and Astrophysics

1. Permitted by law; lawful.
   

2. Of or relating to law; connected with the law or its administration (Dictionary.com).

Etymology (EN): From M.Fr. légal or directly from L. legalis “legal, pertaining to the law,” from lex (genitive legis) “law.”

Etymology (PE): Qânuni, of or relating to qânun, → law.