Today, March 4 - it's Learn What Your Name Means Day
from Namipedia (isn't that a cute name!) at The Baby Name Wizard website, I see that the name Diane is said to be from the Latin: from 'diviana' - meaning 'divine' -also the goddess of hunting and the moon. I'm not sure about this 'diviana' - although I see by googling that it can be a name.
Think Baby Names says Divinia is like Davina (Scottish, Hebrew) and Divina (Latin, Italian), and the meaning of Divinia is "beloved; divine, heavenly". "
Back at The Baby Name Wizard, I tried the app, NameVoyager, and found that according to that, my surmise about the popularity of this name in the 1940s could be true. NameVoyager shows a time/population/popularity graph for the given name you select. In the 1920s, Diane ranked 453 in popularity; then moved up to 22 in the 1940s, and to a high of 17 in the 1950s, but in the 70s, it dripped to 153. This information is for USA and is based on Social Security Administration data. (See the FAQ section.) Dianne/Diana/Dian had somewhat different rates of popularity.
Laura Wattenberg is the originator of The Baby Name Wizard website. She has a book, a monthly column and blog and she's on Facebook snd Twtter too. If you're participating in 'Celebrate Your Name Week', have a look for her.
According to my big old Oxford Dictionary, there's a Diana monkey too - and Diana was once a name for silver (from her association with the Moon, I assume). But it shows Dian as a variant and Dian is also a term for "a beating of the drum at daybreak" from dia - day (Latin).
Well, the goddess thing is all right, I guess, although it seems like a lot of responsibility. I may like the Dian meaning better - after all, I am really a 'morning person'.