I categorize anything related to research (students included) as research meetings. I liberally block off times on my calendar for focused work time on things I’m individually responsible for. I also block off research office hours for doctoral students (rather than scheduling 1 on 1 meetings). For example, I blocked off 4 hours this morning to work on an invited talk.

I didn’t block off time for replying to your question though :) I’m just clearing my inbox while waiting for my 2:30 meeting :)