PracticallyEdible has a nice description of Devil's Food Cake.
Originally, Devil's Food Cake had a medium dense texture. The colour had a reddish tint that was probably caused by baking soda reacting with cocoa powder. In fact, I have an old cookbook (The Day by Day Cook Book, 1939) that contains a recipe for Red Devil's Food Cake. This recipe calls for 2 oz. unsweetened chocolate and 1 tsp. of baking soda.
This question has become blown out of proportion. I was just curious- then I started getting answers that quickbreads and cake are the same thing- which they "obviously" aren't. So I started doing my own research.
Wikipedia says that the term quickbread was probably invented in the US after the discovery of chemical leavening. The Wikipedia references and some dictionaries corroborate this definition. Basically anything leavened with soda is quickbread.
This doesn't work. There are a great many things leavened with soda that can't be called quickbread. A good example is plain old white cake. Obviously this is a semantic issue but one that needed solving.
Two American cookbooks that I consider canonical recipe resources, The Joy of Cooking, and the Better Homes and Gardens cookbook, both have a separate quickbread section. In it are a variety of fruit breads as well as some biscuits and scones.
On Food and Cooking muddied the water a bit by differentiating between quick breads such as biscuits and batter breads such as banana bread. These were grouped together, however, and contrasted against cakes. This book says that cakes are higher in fat and sugar and have a more delicate texture.
Ratio, as linked in this answer, confused the terms a bit more also including a term "quick cake" but it differentiated between the different products with distinct ratios for the flour, fat, and sugar.
With several competing definitions I decided to take an unscientific poll. I called 6 friends in Washington, Utah, Georgia, and Texas. I tried to find a variety of American cultures. Obviously it is biased by the fact that I know all of them.
When asked "What is quickbread to you?" without exception all of them replied "banana bread"
When I followed up with: "What is the difference between that and cake" I received the following answers:
"It is eaten at breakfast"
"It has less sugar"
"It is loaf shaped"
"It is more dense"
"It has a more open texture"
My conclusion is that the historical definition of "anything with soda" is no longer useful. In cookbooks it seems to now be applied to chemically risen baked goods that:
- have as a rule of thumb a particular ratio of flour, fat, and sugar
- have less sugar than cake
- refers in particular to fruit breads, biscuits, and scones
- generally has an irregular vs uniform texture
The popular definition (among my extremely limited, unrandom sampling) adds:
And now I can sleep easily again.
Best Answer
Just to add to rumtscho's answer, there's no standard nomenclature. A similar item consisting of a cake-like thing baked in the shape of a loaf with a decent amount of sugar and eggs could be called any of the terms you use.
On the other hand, I'd say there are some trends in the use of such terms:
If you asked me to bake a "lemon pound cake" for you with no further instructions, I'd use the traditional proportions with no leavening other than creaming butter and sugar, and I'd add some lemon extract and/or other lemon bits like lemon zest. But the result wouldn't be like your linked "pound cake" recipes, other than perhaps being somewhat dense and with a relatively fine crumb.
Modern "pound cakes" modify the proportions quite a bit and often include baking powder and/or baking soda. Others include all sorts of random ingredients (as in the yogurt pound cake you link in the question). But if you search for "pound cake" you will likely find some recipes closer to the traditional version I mention.
So, I'd say the only defining characteristic is its shape -- something with lemons that's baked in a loaf pan. You could bake a lemon pound cake in a different sort of pan, but then I guess it wouldn't be a lemon "loaf."
But again, I'm working off traditional definitions. There's no reason a "lemon bread" recipe couldn't start with a more pound-cake-like template, or some other genre of cake. But if you search for "lemon bread" I assume more of the recipes will be similar to what I describe, compared to searching for "lemon cake" or other things.
I should also note that "lemon bread" could potentially refer to a yeasted bread too, which would be quite a different thing. It would likely still be somewhat sweet, but the technique and resulting texture would be completely different from a cake or a "quick bread" (which, despite its name, is basically a cake generally baked in a loaf pan).
To summarize, I think the difference between these terms lies not in what is common between them, because (as I noted) you can easily find similar results that would all use different names in their recipes. There's substantial overlap. I think the difference lies instead in what sorts of things might come up in a search for some of these terms but which would not qualify under all categories -- for example, a traditional pound cake baked in a bundt pan would not be called a "lemon loaf" or "lemon bread." A yeasted lemon bread would definitely not be called a "pound cake," nor likely would most "quick bread" type lemon loaves.
(Minor final note: I do disagree slightly with rumtscho that a "lemon bread" will typically be less sweet than a "lemon pound cake." Traditional pound cakes have so much butter and eggs that they aren't necessarily very sweet by modern (American) cake standards. And many quick breads I've had are quite sweet, but both cakes and "breads" can vary significantly. Nor would I say "breads" are necessarily less "aromatic," as quick breads are traditionally a showcase for ingredients from carrots to zucchini, and from bananas to lemons, such that quick breads often traditionally had a higher proportion of flavorful ingredients that would have disrupted the texture of a standard cake. But again, usage may vary.)