OEM means original equipment manufacturer.
But coming to regularly pronounced medical device industry terminology it is misleading.
OEMs are manufacturers who resell another company’s product under their own name and branding.
For example, company A is a manufacturing company produces blood pressure monitoring apparatus. Company B has plan to lauch blood pressure monitoring apparatus, but company B has no manufacturing capability for the same. So, company B will first register a trademark and get the product manufactured from company A. That means company B will resell the company A’s brand under own trademark.