I got into a little usage discussion with a commenter on Tracey Taylor's fine blog about East Bay real estate. (Tracey was riffing on a post I wrote about the meaning of Main Street, so yeah, this is what you might call logrolling.)
I knew I was right, but I wasn't sure why. So I did some research.
Commenter David used the word homogenous in his assertion that Berkeley and San Francisco lacked true demographic diversity. I responded that, regardless of whether the assertion is true, the correct word here is homogeneous. David apparently thought I was critiquing his spelling; he came back with a dictionary definition for homogenous and a boast that he was the Wisconsin State spelling bee runner-up.
Yes, homogenous is a dictionary word. David spelled it correctly. It just isn't the right word in this context.
Homogenous (emphasis on the second syllable) means "similar in makeup because similar in descent." The Columbia Guide to Standard American English (1993) gives this example: "These animals are homogenous, as their similar physiology makes clear." Words @Random, from dictionary publisher Random House, explains that homogenous is a technical term in biology ("The forelimbs of mammals and fishes are homogenous").
Homogeneous (emphasis on the third syllable, with a long e vowel) means "of the same kind or structure; of like composition." CGSAE's example: "It was a homogeneous community, its members holding remarkably similar values." (Or: homogenized milk, in which the fat globules are thoroughly emulsified throughout the liquid. Note: In my original post, I had this example in the wrong place. See Regan's comment, below.) That's what David meant, and why his word choice should have been homogeneous.
Both homogenous and homogeneous are composed of Greek word parts that mean "of the same kind." But, notes Words @ Random, "Homogenous is properly limited only to this biological use, so if you're not writing about this, the word you want is homogeneous."
The opposite of homogeneous is heterogeneous. The opposite of homogenous, rarely seen outside scientific literature, is heterogenous.
Hope I've cleared that up.
This reminds me of a quote from the brilliant Anna Russell routine "How to Write a Gilbert and Sullivan Opera":
"You start with a homogenous chorus. Now, I know some of you are going to say 'that's not homogenous, that's homogeneous.' But no, I mean homogenous, as in milk."
Love the blog!
Posted by: Tonia | October 10, 2008 at 11:21 AM
I'm with you up until "homogenized milk." It was always my understanding (as someone whose tenth-grade science teacher drilled into his skull the distinction between homogenous and homogeneous, and in fact used homo milk as an example) that homogenized milk is made homogeneous.
That is, whole milk will tend to separate into two layers of different composition: cream on top and milk on the bottom. This arrangement is described as heterogeneous -- the opposite of "having like composition or structure." In contrast, homogenized milk is made not to separate, and is therefore homogeneous.
Posted by: regan | October 10, 2008 at 04:09 PM
@Regan: I stand corrected on the milk issue!
Posted by: Nancy Friedman | October 10, 2008 at 08:39 PM
This was so interesting. Thanks for pointing that out. I would have skipped over David's comment, understanding what he meant and never thought about the two different words.
Posted by: Susan | October 11, 2008 at 12:00 PM