Genesis 1:1 בראשית ברא אלהים את השמים ואת הארץ׃
Question: Why did the Author of Genesis choose the word בראשית instead of בראש?
I am pretty sure that the word ראשית is derived from ראש, but I am not entirely sure why one would be prefered over the other in this verse. I know ראש is commonly translated as "head," but can also be translated in other ways, such as "beginning" in Judges 7:19 and elsewhere. And I guess a beginning is like a "head" of time, so it kind of makes sense that ראש can be used to refer to a beginning. I know ראש can also be used to refer to the first or most preferred of something, which one might call the "head" of something.
The thing is, ראשית also has a similar range of meanings. It can mean "beginning," but also "first" (Numbers 24:20) or "firstfruits" (2 Chronicles 31:5).
So, I don't see much difference between a ראש and a ראשית. It seems that one difference is that ראשית is never used to refer to the physical part of the body containing the brain, at least not in Scripture. (If it is used in this sense elsewhere, however, that would be interesting. Please inform me if this is so.)
By the way, it seems very elegant that the second word of Genesis, ברא, takes its consonants from the first word. But this neat little poetic trick would still work if בראשית ברא were changed to בראש ברא. But, taking into account Masoretic vowels and the number of syllables, could it be that "בראשית ברא" sounds better to the ear?