an institution that issues something (securities or publications or currency etc.)
"The bank acted as the issuer of the new bond securities to fund its expansion projects."
One who issues, emits, or publishes.
"The newscaster was considered an issuer of important public information during the crisis."
In plain English: An issuer is someone who creates and sells something, like money or stocks, to people.
"The bank is the issuer of this credit card."
The word issuer comes from combining issue with the suffix -er to denote a person or thing that issues something. It entered English as a straightforward formation based on the existing verb issue without any shift in its core meaning.