Here's a quick post about the differences between some different types of casual kimono.
KIMONO is a general term used for any of the long style of Japanese traditional robes, but can also be used more loosely to describe other garments such as haori (a "kimono jacket"), hakama ("kimono pants" - OK, that's a stretch, but I've heard it!) or any of the styles "wedding kimono" (uchikake, kakeshita, shiromuku). To be sure, every "kimono" fits into a sub-category with a different Japanese name which describes more detail about the intended wearer, event, etc. For example, a tomesode is a kimono with family crests reserved for formal events:

....whereas a kosode is for more casual use, such as shopping or visiting friends.

You could google these terms to see the many different types of Japanese garments that might be called "kimono": furisode, juban, nagajuban, uchikake, kakeshita, miyamairi, haori, michiyuki, koto, kurosode, kosode, odori kimono, hanten, happi, neneko, yogi, dochiurgi, samue...
YUKATA is the term used for a specific style of cotton kimono, usually unlined, intended to be worn at summer festivals with a simple obi sash. Versions for women are often colorful florals but are also trditionally blue and white. Versions for men tend to be two-tone geometrics, though other darker colors and various designs are common these days. You might find cotton kimonos that are not yukata - that is, they may be for summertime or countryside wearing but do not have a "festive" patterning.


NEMAKI is the term for a cotton "lounging" kimono, used like a bathrobe. These are often used at resort and spas in Japan and they tend to be blue and white with a very small geometric repeated pattern. The sleeves are "western style" (narrow), there's at least one front patch pocket, and the belt is the same color as the robe and narrow. These aren't worn out of the house in Japan. Contemporary nemaki often have floral prints for women but keep the geometric prints for men.


Hope that's useful info! I have more info (and of course lots of kimono, yukata and nemaki for sale) on my website, www.kyotokimono.com.