What does the Polish prefix U- mean?

Factual Questions
1

Specifically, before the noun krzew, “bush.” What does “Ukrzew” mean?

Thanks in advance.

2

U is just a general locative preposition meaning “by, at, of, on”.

3

I’ve never heard of this word in Polish, and Google has not a single reference to it. “U” as a preposition usually means “at” or “by.”

4

Could it be an obsolete word? The last name Zakrzewski means ‘beyond the bush.’

Cites:

http://www.polishroots.org/surnames/surnames_23.htm
http://www.ancestry.com/search/SurnamePage.aspx?html=b&ln=Zakrzewski&sourcecode=13304

I was trying to get the meaning of the more rare surname ‘Ukrzewski.’ I guess it means ‘by or at the bush/thicket.’

Thanks.

5

http://www.poltran.com/odp.php4?q=2&direction=2&word=krzewKrzew is still a perfectly good Polish word from what I can tell.

6

Once more, with coding:

Krzew is still a perfectly good Polish word from what I can tell.

7

This I know. In that case “u krzew” would mean something like “by the bush” in English.

8

Oh, and “-ski” is a masuline adjectival ending in Polish. ("-ska" being the feminine equivalent.) So basically, yeah, a name like “Jacek Ukrzewski” would mean “Hyacinth, [who lives] by the bush.”