Explanation. The term is derived from the Latin ex (out of) and planare (to make level) and alludes to the concept of clarification through one of various means, e.g., the demonstration that the idea under discussion can be deduced from certain simpler premises, or the division of the idea into simpler elements, or by some combination of such procedures. Explanation can be on varying levels, e.g., if a child asks why the streets are wet we may "explain" the fact by saying that the clouds are pouring rain on them, but that kind of explanation, adequate though it might be for the circumstances, would not satisfy a student of physics or metereology. Modern philosophers have in various ways provided accounts of the nature of the procedure of explanation, but all conform to the general pattern here described. That which calls for explanation is technically called the explanandum, while that which provides the explanation is called the explanans.

Geddes MacGregor, Dictionary of Religion and Philosophy, New York: Paragon House, 1989

explanation : (nt.) visadīkaraṇa; vivaraṇa. (f.) vibhāvanā; vaṇṇanā; atthakathā.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]