The term 'Spiny Tree or Shrub' can be summarized as a plant with thorns or spines. The crossword solution for this term is ACACIA, which is a genus of trees and shrubs that are native to Africa, the Middle East, and parts of Australia. These plants are known for their spiny branches and leaves, and they produce yellow or white flowers. Acacias are often used in landscaping and are popular ornamental plants.