Efflorescence/ˌefləˈresns/ Definition 1 of 4Pro Tip 1/3Technical Term Used in construction or geology, not in everyday conversation. The mason discussed the efflorescence affecting the brickwork. Pro Tip 2/3Visual Cue Indicates a visual problem on surfaces; can be a sign of dampness. Efflorescence on the patio suggests water is seeping through. Pro Tip 3/3Material Specific Occurs on stone, concrete, or brick surfaces, not on metals or plastics. The ancient ruins exhibited efflorescence, giving them a haunted look.