The term 'solemn assent' is a phrase used to express agreement or acceptance of something. The crossword solutions for this term are 'AMEN' (4 letters), 'Ido' (3 letters), and 'Sobeit' (6 letters). 'AMEN' is a Hebrew word meaning 'so be it' or 'let it be so'. It is commonly used in religious contexts to signify agreement with a prayer or statement. 'Ido' is a shortened form of the phrase 'I do', which is used in marriage ceremonies to signify agreement to the marriage. 'Sobeit' is an archaic English phrase meaning 'so be it' or 'let it be so'. It is used to express agreement or acceptance of a statement or proposal.