Good question, Bob. They are NEARLY synonymous, excepting that a nook is most often defined as a corner, and a cranny is most often defined as an opening.
To quote Wiki:
nook (nŏŏk)
n.
A small corner, alcove, or recess, especially one in a large room.
cran·ny [kran-ee] Show IPA
–noun, plural -nies.
1.
a small, narrow opening in a wall, rock, etc.; chink; crevice; fissure: They searched every nook and cranny for the missing ring.
2.
a small out-of-the-way place or obscure corner; nook.
I'm naming my house "Taylor's Knoll," b/c it sits on a knoll, and my apt. in the lower level, "Taylor's Cove,"
"a sheltered nook." Taylor was my grandmother's family name & I inherited the house from her.
There's an upper driveway for the house & a lower driveway for my apt., so I plan on doing signs at each driveway. Cool, huh?
Thanks, D.....always wondered. Guess i could have googled 'em, but this was more fun.
Now my Yankee Girl is all confused and is Googling "Crooked Nannies".......should be interesting.
lmao! my yankee guy was scrumptious tonight. I know, off track, but hey, you started it. '-)
He sent me the sweetest texts & emails. And on the phone & Skype- oh, my goodness! He just slays me.