极限抗拉强度是在「外力作用下，材料抵抗永久变形和破坏的能力」，也可翻译为极限拉伸强度，简称强度。

根据外力的作用方式，有多种强度指标，如抗拉强度、抗弯强度、抗剪强度等。当材料承受拉力时，强度性能指标主要是降伏强度和抗拉强度。

注意强度和硬度是本质上不同的概念。玻璃等硬而脆的物质虽然硬度大（变形与外力之比小）但强度小（在断裂之前能承受的总外力小）。对于同系列的金属，此二者可以有一定的对应关系。强度测量往往需要彻底毁坏材料，而硬度试验则毁坏较小或不毁坏。所以校定的硬度强度换算关系被用来由硬度推算强度。

是金属材料的在外力作用下抵抗永久变形和断裂的能力。工程上常用来表示金属材料强度的指标有屈服强度和抗拉强度。

Ultimate tensile strength (UTS), often shortened to tensile strength (TS) or ultimate strength, is the capacity of a material or structure to withstand loads tending to elongate, as opposed to compressive strength, which withstands loads tending to reduce size. In other words, tensile strength resists tension (being pulled apart), whereas compressive strength resists compression (being pushed together). Ultimate tensile strength is measured by the maximum stress that a material can withstand while being stretched or pulled before breaking. In the study of strength of materials, tensile strength, compressive strength, and shear strength can be analyzed independently.