It's not that easy Richard. Some words have very precise meanings: hippocampus, 2,4-dinitrobenzene, cementite, ampere. Most words are a lot less precise: crane, ommelette, tuxedo, barilla, straight- and there may be some argunment as to whether a specific item is covered by the word. Other words still cover a range: beer, yellow, European. And for some others, like truth, beautiful, faith, patriotism, terrorism, it's difficult to say if they have any meaning at all.

Folk is more like beer and yellow than cementite or terrorism.