James Landau:
> How would you say "oil", in the sense of
> petroleum, in Klingon?

I'd use one of the following depending on the occasion:

'an'or nIn
fossil fuel

betgham 'an'or nIn
liquid fossil fuel

bIQSIp ghav je nIn
hydrocarbon fuel

betgham 'oHbogh bIQSIp ghav je nIn'e'
hydrocarbon fuel which is liquid

Of course the last choice is a rather long construction, but since klingon is ok with g**damn crap like the constructions one uses for full/crescent moon, then I'd consider it quite pharisaic for someone to complain..

Anyways, the way to approach a missing word is simple:

You just look up for synonyms in a thesaurus, and/or you look up the word in a dictionary. Usually, a word missing in the perfect language of klingon, can be described by ideas taken from its' dictionary definition.

~ Dana'an
the truth hurts, right?