I have had to learn the actual meaning of this word, but it sounds so cool I could see this becoming my catchphrase:

• "Hot? That girl was diatomaceous!"
• "You couldn't be more diatomaceous if you tried."
• "Some things are pernicious. And some things are diatomaceous."

It is an old and sharp word.

It is a good word, and Marine Biology related. Therefore, Science Mod approves.

I want to do this without cheating i.e. googling - I know that a diatom is some kind of unicellular life, right? So is diatomaceous linked to that?

Yes.

You certainly couldn't get the meaning of the word from the context of the examples James listed.

I knew about the word from its relation to dynamite.

I correctly guessed that it had something to do with diatoms. I gather that it is (or can be) a geological term describing limestone formed from diatom remains?

Googled it and came up with this:

http://en.wikipedia.org/wiki/Diatomaceous_earth

Diatomaceous? Wasn't he that ancient Greek dude who invented the diatonic scale in Western music theory?

When I was a kid we had an above-ground swimming pool with one of those large filters on the side. Once a month, we had to open up the filter and dump in a few cups of diatomaceous earth.

I don't know what it's purpose was, but we had a big 50 pound bag of the stuff next to the pool filter. It was called "diatomaceous earth", but it was a white heavy powder really.

According to Wiki:

The most common use (68%) of diatomaceous earth is as a filter medium, especially for swimming pools. It has a high porosity, because it is composed of microscopically-small, coffin-like, hollow particles. It is used in chemistry under the name Celite as a filtration aid, to filter very fine particles that would otherwise pass through or clog filter paper. It is also used to filter water, particularly in the drinking water treatment process and in fish tanks, and other liquids, such as beer and wine. It can also filter syrups and sugar. Other industries such as paper, paints, ceramics, soap and detergents use it as a fulling material.

I was supercalifragilisticalling it on purpose.

It's a perfectly cromulent word.

Eschew obfuscation, guys.

I always do.

Not that anyone cares, but I am getting food grade diatomaceous earth for pest control. That's how I came across the word.

We've been seeing the coming attractions for director Charlie Kaufman's new movie titled Synecdoche NY (an obscure pun on Schenectady, I suppose). My Webster's dictionary uses so many words in such a roundabout way to define "synecdoche" that I figure I'm better off never using the word in conversation. Unless we're talking about the movie.

Diatoms are cool. At the abyssal depths their casts fall thru the water column like rain, piling up on the ocean floor. Like bat guano. Just piling up for millennia. Cool beans.

My penchant recently for referring to a woman as a "double x" would be an example of synecdoche.

But would be very hard to pronounce by a crapulent individual.

Not a SIMPSONS fan, huh?