* In-Ear Monitor: This is the most common meaning, referring to small earphones worn by musicians on stage to hear their own performance and the mix of other instruments.
* Intellectual and Developmental Disabilities: This abbreviation is used in the medical and educational fields.
* Intestinal Enteric Microbiota: This refers to the collection of microorganisms living in the intestines.
* Internet Engineering Management: This is a professional designation related to internet engineering and management.
* Integrated Enterprise Management: This refers to a system for managing all aspects of a business.
To determine the correct meaning, you need to consider the context in which the acronym is used. For example, if you're reading about a musician's equipment, IEM most likely refers to In-Ear Monitors.