The term has been defined as Original Equipment Manufacturer for half a century at least and it's pretty clear to most of us what it means without ambiguity. I'm not sure why the confusion. Whoever made the stuff is the OEM. The only possible confusion is in the word made. Since complex products consist of many components, some of which are outsourced, it's impossible to know exactly which pieces were made by the manufacturer, and which were not. As a result the term generally refers to the manufacturer or brand of the "finished" product. An OEM part or accessory is one made or marketed by the manufacturer of the finished product and is usually branded as such. A non OEM part or accessory is one created and or marketed by an unrelated third party, which may look similar and will presumably work seamlessly with that product.

If I had my way (fat chance of that), use of the term "OEM" would be banished from the language and the forum. It is a term that keeps changing meaning periodically and is ambiguous because of it. For example,a recent post used the phrase, "OEM Nikkor lens" apparently meaning "lens built by Nikon". That, however, is not in keeping with the current use of the term. It has changed drastically over the years. Back in the '60s, it was used as an acronym for "Other Equipment Manufacturer" meaning equipment, usually peripherals, not built by the maker of the mainframe to which they were attached (e.g., you had OEM equipment attached to your IBM m/f if you had Potter tape drives or EMC disk drives connected to it). Now it has an entirely different meaning. From Wikipedia "An Original Equipment Manufacturer (OEM) is a company that produces parts and equipment that may be marketed by another manufacturer. For example, if Acme Manufacturing Co. makes power cords that are used on IBM computers, Acme is an OEM." There have been other definitions attached to the acronym over the years. It has been adopted for use is several unrelated fields as well.

If I had my way (fat chance of that), use of the term "OEM" would be banished from the language and the forum. It is a term that keeps changing meaning periodically and is ambiguous because of it. For example,a recent post used the phrase, "OEM Nikkor lens" apparently meaning "lens built by Nikon". That, however, is not in keeping with the current use of the term. It has changed drastically over the years. Back in the '60s, it was used as an acronym for "Other Equipment Manufacturer" meaning equipment, usually peripherals, not built by the maker of the mainframe to which they were attached (e.g., you had OEM equipment attached to your IBM m/f if you had Potter tape drives or EMC disk drives connected to it). Now it has an entirely different meaning. From Wikipedia "An Original Equipment Manufacturer (OEM) is a company that produces parts and equipment that may be marketed by another manufacturer. For example, if Acme Manufacturing Co. makes power cords that are used on IBM computers, Acme is an OEM." There have been other definitions attached to the acronym over the years. It has been adopted for use is several unrelated fields as well.

If I had my way (fat chance of that), use of the term "OEM" would be banished from the language and the forum. It is a term that keeps changing meaning periodically and is ambiguous because of it. For example,a recent post used the phrase, "OEM Nikkor lens" apparently meaning "lens built by Nikon". That, however, is not in keeping with the current use of the term. It has changed drastically over the years. Back in the '60s, it was used as an acronym for "Other Equipment Manufacturer" meaning equipment, usually peripherals, not built by the maker of the mainframe to which they were attached (e.g., you had OEM equipment attached to your IBM m/f if you had Potter tape drives or EMC disk drives connected to it). Now it has an entirely different meaning. From Wikipedia "An Original Equipment Manufacturer (OEM) is a company that produces parts and equipment that may be marketed by another manufacturer. For example, if Acme Manufacturing Co. makes power cords that are used on IBM computers, Acme is an OEM." There have been other definitions attached to the acronym over the years. It has been adopted for use is several unrelated fields as well.

All the other posts aside - language, at least one still used (not a "dead" language like Latin,in most cases) change and grow just like a living thing. Sometimes we like the changes, sometimes we don't and often we don't care one way or another. But language changes, in particularly the meaning/uses of words. Sometimes the change starts as slang, sometimes in the jargon used in one profession or another and though I hate to say it as a retired teacher sometimes just from poor language skills on the part of a large segment of society.
And don't even get into adaptation of words from other languages.