Open primaries

[⛄]

What exactly are open primaries? Does that mean that one can vote in any political party's primary they want? Even without being a member of that party?
And can you also participate in more than one party's primary?

[muon2]

There are a number of types of open primaries. I'll give two examples, but there are many other variations.

The state runs a primary for each qualifying party with separate ballots for each. Voters are free to choose whichever ballot they prefer when they enter the poll for the primary. The vote is cast for candidates in that chosen party in the primary.

The state runs a primary and lists all candidates for an office with their declared party affiliation. Voters may vote for candidates from different parties for different offices.