What's a Semi-Open Primary? How's it different from an Open Primary?

Question

What's a Semi-Open Primary? How's it different from an Open Primary?

Answer 1

In a semi-open primary, the parties are given the option of inviting anyone to vote in their primary. In an open primary, the party has no option who can vote in their primary. The semi-open is the best option because it allows the party to decide if they want to use the option or not.