This is the 1983rd most frequent Japanese word.
みな
"みな" means "everyone" or "all."
In this sentence, 'みんな' refers to a group of people collectively as 'everyone'.
みんなが集まって話し合いました。
Everyone gathered and discussed.
Here, 'みんな' is used to mean 'all' in reference to a group that includes the speaker.
私たちはみんな楽しんでいます。
We are all enjoying ourselves.
In this example, 'みんな' denotes 'everyone' individually within a given context.