An explanation of the origins of the name Bukit Batok, as given by wikipedia:

A more ribald explanation has it that the two hills in the area looked like green buttocks to the British, a word which suffered verbal mutilation among the Chinese to finally emerge as batok.

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*Why buttocks and asses? Why not breasts? =p

And of Bukit Timah:

Some say that timah is an abbreviation of Fatimah, a popular Malay girl's name.

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Morale of the story: Seeing how people come out with names/stories to explain words, i guess it is important to remember our history lessons. Who knows, maybe in the future, people will be speculating that the name Raffles institution came from a Rubbish-collector (raffle = rubbish); or that the name Hwa Chong is derived from the clock tower in the school (Zhong is clock in chinese). Or maybe, Nanyang is just a verbal mutilation of the word niang-niang (Niang Niang Chiang = feminine). Seeing how the names of our places have such wonderful etymologies, i wont be surprised.