OEM stands for Original Equipment Manufacturer and describes a company that builds products using components from other companies. It can also be that the OEM simply re-brands a product which is completely made by a manufacturing company called an ODM (Original Design Manufacturer).
Historically, this could apply to many different industries, but in the context of our websites, it mostly applies to PC manufacturers and Mobile manufacturers. However, that’s also true for many other types of products such as surveillance cameras, action cams, etc…
Many if not most consumer electronics sold will have a consumer-facing OEM, which has a brand and can provide support to buyers. These OEMs rely on ODMs to design and manufacture their products. Sometimes, OEMs control the whole design process and other times, the ODM drives everything and sells a finished product to the OEM, which simply rebrands it.
Dell, HP, Lenovo are typical examples of OEMs, but this definition applies to many other companies.