硅氧树脂亦称为硅酮、硅利康（polymerized siloxanes或polysiloxanes，俗称silicone），是一个介于有机与无机的聚合物，其化学式为[-R₂SiO-]_n，其R=甲基、苯基等有机集团。这些材料由无机硅氧键骨架（...-Si-O-Si-O-Si-O-...）和以共价键和硅原子结合的支链有机基团组成。通过控制骨架的长度、有机基团的种类和骨架的交联，可得到具有不同性质的硅氧聚合物，从液体的硅油到有柔软弹性的硅凝胶、硅橡胶和刚性的硅树脂。最常见的种类为线性的聚二甲基硅氧烷（PDMS，一种硅油）。第二常见的硅脂材料种类是基于硅树脂分子形态基于树状或笼状硅氧键。硅橡胶有时也被简称为硅胶，但英文中硅胶（silica gel）和硅酮（silicone）是性质和用途不同的含硅化合物。

Silicone rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers are often one- or two-part polymers, and may contain fillers to improve properties or reduce cost. Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from -55 °C to +300 °C while still maintaining its useful properties. Due to these properties and its ease of manufacturing and shaping, silicone rubber can be found in a wide variety of products, including: automotive applications; cooking, baking, and food storage products; apparel such as undergarments, sportswear, and footwear; electronics; medical devices and implants; and in home repair and hardware with products such as silicone sealants.