Not quite, and the specifics can matter a lot in cases like this. The way it was explained to me that made the most sense, was to imagine if there were two types of plagiarism: felony and misdemeanor. Felony plagiarism is taking someone else’s idea and claiming it as your own, or directly quoting an original idea without putting it in quotes, and pretending it was your idea all along. Misdemeanor plagiarism is not properly citing someone else’s idea, or simply misattributing a quote or well-established concept. Not that hard to do to be honest, and while the latter is careless and shouldn’t ever happen, Gay was accused of what would be a misdemeanor plagiarism. She didn’t steal anyone’s ideas, she just did a bad job at attribution. The distinction matters, though what she did still isn’t good, to be fair.