I'm So [X], Even My Acronym

'X' is a prefix that in most information technology usages means "an underlying definition or description." 'X' derives from Greek, meaning "among, with, after, change." Whereas in some English words the prefix indicates "change", in others, including those related to data and information, the prefix carries the meaning of "more comprehensive or fundamental."

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Picture 1: Let's call him 'Y'. He popularized 'X' through one of his works, i.e Picture 4.

Picture 2: Kind of helps to guess 'Y'.

Picture 3: ID the blurred part, you get the answer right away.

Oh yeah, the title of this question helps a lot.

ID 'X' and 'Y'.

Join/Connect/Combine/Relate.