Common words:
* How
* Now
* Wow
* Bow (noun, like a ribbon)
* Cow
* Grow
* Know
* Show
* Snow
Less common words:
* Crow
* Flow
* Glow
* Gow (an archaic word for "go")
* Hallow
* Hollow
* Plow
* Slow
* Vow
Words with "ow" at the end:
* Allow
* Bellow
* Clow
* Frow (to frown)
* Gallow
* Hallow
* Pillow
* Sorrow
* Willow
Words with "ow" in the middle:
* Downtown
* Endow
* Fellow
* Follow
* Hollow
* Mellow
* Shadow
* Window
Bonus:
* "Ow!" (an exclamation of pain)
This list provides a good variety of words containing "ow." Remember that there are many more words out there, and this is just a small sample!