I don't know Latin either, but saw this phrase posted a lot yesterday in regards to the Knox/Sollecito decision. So I looked up the meaning, liked it and posted it here on DU. I really should have posted the meaning! Duh!
From wisegeek: http://www.wisegeek.com/what-does-in-dubio-pro-reo-mean.htm
The Latin phase in dubio pro reo translates "as in doubt, for the accused". A more expanded definition is that courts and juries must take the side of an accused party when there are doubts about the charges. This is connected to reasonable doubt and to presumed innocence, which are a foundational part of many justice systems. It also affects the rule of lenity, when judges must make interpretive decisions about ambiguous laws in favor of someone who is accused.
Throughout history, many judicial systems have been established on the principle that an accused person cannot be convicted if reasonable doubt exists. The exact definition of what doubts are reasonable is definitely a gray area. In most cases, though, the idea of in dubio pro reo prevails. All a defendant must do to retain his innocence is establish credible doubt about a prosecutors case.
For example, a jury that hears conflicting but reasonable testimony about the whereabouts of the defendant on the night of the crime is being given an opportunity to doubt the charges. When juries are unsure, they cannot vote for a conviction. Instead, they must find for the accused based on the underlying principle embodied in dubio pro reo.
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