I DO' (3 letters) The term 'Word Said at an Altar' can be summarized by two crossword solutions: AMEN (4 letters) and 'I DO' (3 letters). AMEN is a Hebrew word that is commonly used in religious contexts, such as in prayer or worship. It is often used to express agreement or acceptance of a statement. 'I DO' is a phrase that is commonly used in wedding ceremonies, when the couple being married expresses their commitment to each other.