Shulchan Arukh, Orach Chayim 5/שולחן ערוך·אורח חיים ה׳

1[Laws Regarding The Proper] Intent [When Reciting] The Blessings. Containing 1 Se'if:One should have in mind the meaning of the words when reciting blessings. When articulating the Name (ie. י-ה-ו-ה), one should have in mind the meaning of the Name as it is pronounced - Adon-ai (א-ד-ו-נ-י): that He is Lord over all. And one should have in mind [the meaning of the Name] as it is spelled with a Yud-Hei (ie. י-ה-ו-ה) that He Was (ה-י-ה), Is (ה-ו-ה), and Will Be (י-ה-י-ה). And when articulating the Name Elo-him (א-ל-ה-י-ם), have in mind that He is Strong, Omnipotent, and Master of all powers.