The term small and medium enterprises (SME) refers to businesses whose personnel numbers, revenue, or other factors fall below certain limits.
What limits apply to SME varies by country and entity doing the classification. For example, in Switzerland the Federal Statistical Office considers enterprises with less than 250 employees to be an SME while in Canada the limit set by Industry Canada is 500 employees.
In the U.S., the Small Business Association typically defines “small” as less than 500 employees (with exceptions for some industries) while the Department of Energy defines small and medium-size manufacturers as having gross annual sales below $100 million, fewer than 500 employees at the plant site, and annual energy bills more than $100 thousand but less than $2.5 million. 
- Common Language in Marketing Project, 2018.