Hmmm, my dictionary (the Concise Oxford Dictionary, Ninth Edition, 1995)
gives only the commonly understood meaning for meticulous, though it does
give the etymology that kessenich mentions.
It also defines punctilious as being particularly attentive to
formality or etiquette, which would not be synonmous with
how people use meticulous.
I cringe inwardly when I don't feel free to use a
word that means exactly what I want to say, because it is either
generally unknown or, worse, known incorrectly.
Just look at what happened when David Howard correctly used the
word niggardly. The pink monkey has to decide
whether to be emself and take the beatings, or blend in and possibly
feel badly about emself.