Whose definition? Support to whom?
For example:
An original equipment manufacturer (OEM) provides components for another company’s product and works closely with the seller of the finished product.
www.investopedia.com
An original equipment manufacturer (OEM) is a company whose goods are used as components in the products of another company, known as a value-added reseller (VAR). The VAR works closely with the OEM, which often customizes designs based on the VAR's needs and specifications
or
An Original Equipment Manufacturer or OEM is a company that manufactures and sells products or parts of a product that their buyer, another company
corporatefinanceinstitute.com
An Original Equipment Manufacturer or OEM is a company that manufactures and sells products or parts of a product that their buyer, another company, sells to its own customers while putting the products under its own branding. OEMs commonly operate in the auto and computer industries.
or
OEM, meaning Original Equipment Manufacturer, relates to a company that supplies equipment to another one. For more information, click here.
toolsense.io
The abbreviation stands for “original equipment manufacturer”. It refers to any company that manufactures products for or parts designed to be incorporated into an end product from a different company.
All 3 of those seem to fit Magna, which builds parts and cars for other companies to put their name on and resell, rather than magna directly selling the cars to customers themselves....and Magna provides support to the reselling car companies, not end consumers.