Based on the answer to this M.Y. question, stating that קדוש is an adjective, wouldn't the expression הקדוש ברוך הוא be grammatically incorrect? Shouldn't it be הקודש ברוך הוא , since קודש is a noun?
Have we been saying it incorrectly all along? The Siddur uses הקדוש ברוך הוא in many places (See end of יקום פורקן paragraphs as a sample.) Have we been doing this wrong for so many years? If the term is grammatically incorrect, how / why did this error begin, esp. in the Siddur?