The term 'joined harmoniously' can be described by the word 'DOVETAILED', which is a 10-letter word. Dovetailing is a type of woodworking joint that is used to join two pieces of wood together in a way that creates a strong and aesthetically pleasing connection. The joint is made by cutting each piece of wood into a shape that resembles a dove's tail, hence the name. This type of joint is often used in furniture making and other carpentry projects, as it provides a secure and attractive connection between two pieces of wood.