Reinforce/ˌriːɪnˈfɔːrs/ Definition 1 of 3Pro Tip 1/2Physical Strengthening Used when physical objects like buildings or structures are made stronger or more secure. The workers used steel beams to reinforce the old walls. Pro Tip 2/2Adding Details Applies when extra information or clarification makes an argument or idea more convincing. The lawyer reinforced his argument with new evidence.