First of all, we need to understand the "anatomy of a hat" - what are the different parts that make up a hat called?
- Crown: The upper part of the hat is called the "crown". An actual crown is pretty much just a ring that sets on top of your head; the crown of a hat is exactly the same thing.
- Crown shape: The top of the crown can be domed, flat, or "dented" into various shapes. The crown shape plays a significant part in making a hat a certain style.
- Hat band: Hats are often decorated with a ribbon or strip of material (fabric, leather, beading, etc.) circling the base of the crown. This hat band may be embellished with a knot or bow or other fancy details.
- Hat decoration: Certain styles of hat have a very specific type of decoration tucked into the hat band, which may range from small feathers to hugely elaborate loops and bows.
- Brim: The brim juts out from the base of the crown and shades the face. The brim may be any width, from narrow to wide; it may be not-existent (e.g., on a pillbox hat); or it may be a partial brim (e.g., on a baseball cap).
- Underbrim: The underside of the brim may be lined in a different material or it may simply be the underside of the brim.
- Inner band/sweatband: Exactly what it sounds like: The sweatband absorbs sweat from the brow, and also serves to keep the hat in place. Not all hats have an inner band.
- Inner liner: Not all hats have an inner liner, but sometimes the crown is lined with fabric.
Now we get to the various styles of women's hats. The style is defined by the relative size and shape of some of the various components listed above. There is a large degree of variation in many of these styles, primarily in terms of how they are decorated. It's really the basic structure of a hat that defines its style, although a few types of hats require a very specific style of decoration (e.g., a man's Tyrolean hat is traditionally decorated with a small feather). Let's go in alphabetical order.
A beret is a soft fabric hat with a round, short crown and no brim, although it may have a kind of band at the base, as seen in the second photo above. Traditionally, they are decorated with a small "apple stem" at the top. In the 1940s, they were sometimes worn in a very flat style called a "pancake beret," as in the third photo, above. They have their roots in military garb, and are still worn by military members such as the Green Berets. They are often associated with artists, particularly French painters.
Boater (also called a skimmer)
A boater hat is a straw hat with a medium-width brim and a low, straight-sided, flat-topped crown. Traditionally, it bears a red-on-blue striped hatband with two long tails trailing down the back, as originally worn by Venetian gondoliers, but today the tails are often omitted, and the hatband is more commonly black. Modern variations also change the height of the crown from quite short to relatively tall, and occasionally add a slight dome to the top of the crown. You may also recognize the style as being worn by traditional barbershop groups, and styrofoam versions are sometimes worn at political rallies, likely because of their red, white, and blue colors.
Bowler (or derby)
Although primarily thought of as a men's hat, bowlers can also be worn by women. Generally made of sturdy felt, they have a high, domed crown, and a 2-inch brim that is bound along the edge and turned up at the sides and sometimes all around. If you are of a certain age, you likely associate a bowler with Patrick Macnee from the Avengers television series, or perhaps with Charlie Chaplin. A bowler hat and a derby hat are exactly the same thing, bowler being the British term and derby the American. However, a man's derby hat should not be confused with a woman's Derby hat, which is a highly decorated hat worn to the Kentucky Derby (see "Derby hat," below).
Popularized in the 1920s, a cloche is characterized by being very close-fitting to the head and somewhat bell-shaped, with a brim that may flare slightly or not, or which may be only on the front of the hat. A cloche may be made of wool, fabric, or straw, or even knitted or crocheted. It is often embellished with a hatband and bows, feathers, or flowers placed at the side, back, or front. Famous wearers of cloche hats include Clara Bow and the entire female cast of any version of The Great Gatsby ever filmed.
Cocktail hat (see "Fascinator," below)
Derby hat (or race hat)
Kettle brim (also called up-brim)
Picture hat (or Gainesborough)
Something of a precursor to the Derby hat, a picture hat is an ornately decorated hat with a wide brim, often featured in portraits of wealthy women painted by artist Thomas Gainesborough during the late 18th century, and the style is still popular today. Decorations have ranged from fresh flowers to huge bows to ostrich and marabou feathers to gemstones. Large picture hats are sometimes also called cartwheel hats. Camilla Parker Bowles is often photographed wearing a picture hat, and the "Ascot Gavotte" scene from My Fair Lady is full of marvelous picture hats.
Jacqueline Kennedy nearly single-handedly brought the pillbox into popularity in the early 1960s. Its distinctive round, brimless. straight-up, flat-crowned shape often has a small birdcage veil (which drops just below the eyes) attached, and it may be unadorned or be decorated with ribbons, bows, or flowers on the top. Other famous pillbox wearers include Doris Day and Audrey Hepburn.
The tam is a woman's version of the traditional Scottish tam o'shanter (named after a character in a Robert Burns poem), and is somewhat similar to a beret. It is a soft, brimless hat with a round, full crown, often knitted or crocheted, and topped with a small pom-pom. Modern women's versions often replace the pom-pom with a small button or omit it altogether. The tam is generally worn drooping to the side or the back. Occasionally a small brim is added in front, creating an almost bonnet-like style, as in the third example above.
Let me know if there are any styles you're still confused about, or if I've missed explaining any!