אָחוּ
Although English word "meadow" is in a quite frequent use, somehow its Hebrew equivalent is not. After living in Israel for more than a decade, I didn't know this word. 
Anyway, here is the word: אָחוּ, and according to Even-Shoshan (pretty old though, I have one printed back in 1960) the plural is אַחִים (undistinguishible from אחים / brothers, I guess.)
Shimon Zilberman's dictionary translates it as: meadow, lea, pasture.
This אחו is apparently a segoalte noun (!), and as such its stress falls on the אָ. Well, it's third root letter must be Vav, which is a rare case, especially with segolate - that's probably why it has such a strange vocalization. The word seems to be a big exception from many morphological rules, anyway.
Another word that appears aside אחו is the word כַּר, or כַּר-מִרְעֶה; it's exactly the same כר which is also "pillow".
There is also the word אֲפָר (found in old Even-Shosan), with the same meaning, but I guess this word is really archaic, for a number of reasons.
So here we go:

שמורת אחו בנימינה [1] - I've been here many times, but still, somehow haven't learned the word. This place is beautiful, and Zikhron-Yaakov with its דרך היין and all the nice restaurants is really close.
Links:
[1] http://www.inature.info/wiki/שמורת_אחו_בנימינה