Describing how a material behaves when you pull it. Two related uses. First, and much the commonest, in the fixed phrase tensile strength: how much pulling a material can take before it snaps. Steel has high tensile strength; a piece of paper has very little. Engineers and scientists use this constantly, and it is a measurable number, not a feeling. Second, on its own, tensile can describe something that can be stretched out without breaking — a tensile metal, a tensile fibre. The word is technical. You will find it in engineering, physics, materials science and product descriptions, almost never in conversation. Here is the useful thing behind it: pulling and pushing are different, and materials handle them differently. Tensile force pulls apart; the opposite, compressive force, squeezes together. Concrete is famously strong in compression and weak in tension, which is exactly why builders put steel bars inside it — the steel takes the pulling, the concrete takes the pushing. Once you see that pair, a lot of engineering writing opens up.