yes
The word nightgowns refers to loose garments that are worn to bed.
I was born in 1940. My mother wore nightgowns and as a child, I wore pyjamas.
I would say that, yes, nightgowns are considered apparel. Apparel is just anything that you wear.
One can easily buy and find nightgowns online everywhere. For example like eBay and Amazon are amazing sites to buy simple goods and items such as nightgowns.
One can buy Calida nightgowns onine in eBay, Amazon, or Yahoo shopping. In addition, one can purchase Calida nightgowns in herroom dot com, which sells a lot of items for "her".
Hudson's Bay, Suttle's & Seawinds, and April Cornell are great Canadian stores that sell quality cotton nightgowns. Also, popular chain stores such as Sears and Marshall's can be found in Canada that sell cotton nightgowns.
kmart or walmart
Shadowline nightgowns can be bought from their own website, or from etsy website online. One can also purchase any nightgown from the department stores.
Eileen West nightgowns can be found directly on their official site. Or, one could check at stores such as Nordstrom's or Dillard's, or at a site such as eBay or Amazon.
Yes Yes
I have found them on eBay and on Etsy.
Cotton nightgowns can be purchased from many different stores and retailers. Some examples that sell cotton nightgowns include HerRoom and Lord & Taylor.