An Etymological Dictionary of Astronomy and Astrophysics

1. To make known or state clearly, especially in explicit or formal terms.
   

2. To announce officially; proclaim (Dictionary.com).

Etymology (EN): M.E. declaren, from O.Fr. declarer “explain, elucidate,” from L. declarare “make clear, reveal, disclose, announce,” from → de- intensive prefix + clarare “clarify,” from clarus, → clear.

Etymology (PE): From Kurd. (Sorani) rûnâk, runâg “clear, bright,” rûn “bright, clear,” rûn kirdin “to explain,” variants of rowšanâ, rowšan, rušanâ, → bright, → day.