The correct form is בְּדִיּוּק be-di-yuk However, it's pronounced bi-di-yuk or bid-yuk by many Hebrew speakers. It's just a very common mistake :)

many times, in Hebrew, Shva becomes in spoken Hebrew a tseire or hirik, meaning b becomes be or bi. BTW, not sure what's exactly you mean with this word, it could be pronounced as bi or be - if you want an exact pronunciation please write a sentence...

As Omer rightly says the colloquial way to say it is Bidyuk. And when people want to emphasize they are won't to put a stress on the first (incorrect) syllable, which makes it even funnier.

Thanks, Eyal, for taking the time to leave your valuable comments!

The vowel marking you found in the dictionary is the correct one, even though it doesn't directly represent "bEdyuk". I don't know the reason for this way of vowel marking for this word, it's also very common in biblical text. In general, people pronounce this word BOTH WAYS and both sound correct and natural to us, the native speakers. bEdyuk is the correct way. You could break it down to be (in) and dyuk (precision/accuracy). Which makes sense. Good luck with your studying!