The "dahu" in the Arabic Language means to extend and even out. It is said: "daha" the thing; "yad'hu dahwan". These terms can mean he either evened out and extended it or he threw it and rolled it. It is also said: "the rain daha the stones from the face of the earth," which means it rolled it and washed it away. It is also said: "The horse passed by yad'hu dahwan," which means he is beating his foot on the ground and yad'hu its sand. Also, the ostrich's mad'hi means its laying of its eggs, and "ad'hiha" is the nest where its chicks are born.
Arabic-English Dictionary
The Hans Wehr Dictionary of Modern Written Arabic
Edited by J M. Cowan
ISBN: 0-87950-001-8
Dahdah and Dahdaah: dumpy, Squat, stocky.
Dahraja: to roll.
• Tadahraja: to roll, roll along; to roll down.
( [1], page 272)
Daha: to spread out, flatten, level, unroll. [See: Squat and dumpy in Dahdah above]
Concise Oxford English-Arabic Dictionary
University Press
www.oup.com
ISBN: 0-19-864321-7
Squat: Dahdah.
( [1], page 379)
Roll:
• (motion): dahraja, tadahraj.
• roll over: tadahraj.
• (rotate): dahraj.
Roller: madhala.
So as we clearly see, all of the above Arabic words that are derived from "daha" mean:
1- To extend.
2- To roll.
3- To even out.
4- Causing to become egg-shaped or creating, making or producing eggs
http://www.nooran.org/E/7.htm
hope that helps insha'Allah..
