The term 'Early Christian PULPIT' refers to an architectural feature found in early Christian churches. The two crossword solutions, 'AMBO' and 'MBO', are both related to this feature. 'AMBO' is a Greek word meaning 'raised platform' or 'PULPIT', while 'MBO' is an abbreviation of the Latin phrase 'AMBO minor', which translates to 'smaller PULPIT'. Both terms refer to the same architectural feature, which was used in early Christian churches as a place for the priest to deliver sermons.