Which term identifies the gathering of party members who voted in the party's primary for the purpose of electing delegates to the county or district convention?

The term that identifies the gathering of party members who voted in the patry's primary for the purpose of electing delegates to the country or district convention is: "Precinct Convention" or just commonly known as "Precinct".

Explanation:

A precinct is the lowest level of governmental division in the United States of America, and it is also known in some districts as an election district. They are generally not holders of governmental authorities however they can have influence in the decision making about alcohol, medicines, social projects, etc. they are implemented in elections by town or county. Usually, they are assembled in certain spaces and people go there to exercise their right to choose their representatives.