When is it acceptable to use abbreviations with a customer? If it is a generally understood abbreviation, then it is acceptable. For example, GST is a common term, but only in Canada. However, if the abbreviation is a company or specific term that you only learned when you started selling your product, then don’t. If you didn’t know its meaning before you joined your industry, chances are your prospect won’t either. When in doubt, don’t use the abbreviation!