Sketchbook, visual diary or art journal?

A few years ago, when the creative itch first started to trouble me I decided I needed to equip myself with a sketchbook. I was on holiday and with only one small bookshop  nearby the closest thing I could find was something labelled 'visual diary'. Later, a bit of research turned up yet another possibility... an art journal.

So… sketchbook, visual diary or art journal?

What's the difference?

Which one should a beginner take up?

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