the video is talking (https://youtu.be/4kuhQzbc2Tw?t=76)
"Kind" is a word you've probably heard before. "She is a kind woman.", "He has a kind face." And we mean nice and friendly. Now, you might not be aware that it also is a noun, "as in" category.
I am aware the meaning of what he is saying, namely, "kind" has a meaning of "category".
the speaker uses "as in" there, what does that mean, how do I use it correctly?