A Cappella

So what exactly does that mean?  Well, it refers to unaccompanied singing - specifically but not exclusively - choral singing.  But why a cappella?  Well, big churches, Catholic and Anglican, were constructed in the same way - entrance at the west end, straight aisle from the door to the altar at the east end.  And then off to the sides of the aisle would be smaller side-chapels, designed for private prayer, and often dedicated to some particular saint.  These side-chapels would have their own altars and seating - they would in fact be miniatures of the church itself, with one important difference.  No organ - so if you wanted music in these little chapels, it had to be unaccompanied singing,  The Latin word for chapel is cappella and so unaccompanied singing became known as singing "in the style of a chapel" - or a cappella.