What's the difference between $p(x \mid \theta)$ and $p(x; \theta)$?

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Meaning of probability notations $P(z;d,w)$ and $P(z|d,w)$

Can you tell me the difference between $p(x \mid \theta)$ and $p(x; \theta)$? I know $p(x \mid \theta)$ is the conditional pdf, then what about $p(x; \theta)$?