Cladding meaning : (past tense clad) To clothe. (past tense clad or cladded) To cover (with insulation or another material); to surround, envelop. (figuratively) To imbue (with a specified quality) Clothing; clothes. Any hard coating, bonded onto the outside of something to add protection, such as the plastic sheath around an optical fibre. A weatherproof, insulating or decorative covering fixed to the outside of a building (called siding in the US).