מוֹסָד“foundation”The Hebrew word mosad, "foundation," is the standard form of this noun and the one dictionaries list first. It always appears in the plural, in the phrase "the foundations of" something: the foundations of the mountains that catch fire in the Song of Moses, the foundations of the earth that God marked out in Proverbs and that shake in Psalm 82 and Isaiah 24, and the age-old foundations that rebuilders raise up in Isaiah 58. The spelling mosadah is the same word with a feminine ending, used in exactly the same way, so the two are read together as one word.