main ideas

• centralIn the middle, primary
• coreCentral essential portion
• essenceFundamental nature of something
• thesisAcademic argument requiring defense
• key pointsCentral ideas distilled

summary · gist · crux · takeaway · theme · concept · argument · outline · highlights · substance · heart · foundation · framework · pillars · message · purpose · focus · conclusion

• study aidstutor, note cards, CliffsNotes, crib sheet, study guides
• summariessummary, synopsis, summaries, abstract, abstracts
• outlinesoutline, framework, skeleton, structure, schema
• book summariessummary, plot summaries, novel summaries, synopses, chapter summaries
• tutorialstutorial, how-tos, quick start guide, tutorial video, step-by-step guide
• insightsinsights, lessons, realizations, discoveries, epiphanies