The term 'Diagonal Spar' refers to a type of spar, which is a structural member used in the construction of sailing vessels. The term 'SPRIT' is a five-letter word that is used to describe a type of Diagonal Spar. A SPRIT is a short spar that is used to extend the foot of a sail beyond the end of the boom. It is usually attached to the mast and the boom, and is used to support the sail when it is set.