The term “Tripled Keyword” means that you have used recommended keywords in the three most important places for your video:
In your video's title.
In your video's tags.
And in your video's description.
If you have Tripled Keywords, then you are using your keywords in the best possible way to increase your SEO on your video.
Watch as Rob explains more and provides some additional tips on how to increase your Tripled Keyword score: