An ambigram is a word that reads the same right-side-up and upside-down. MOW is a natural ambigram, for instance, but any word can be flipped if the right graphic artist gets his hands on it.

I like him less each time I see him.

Salt, sugar, and acid all act as preservatives when making pickles.

It can also be used for class C fires where the nonconductivity of the extinguishing agent is important.