Pardon my ignorance, but what's the difference? Honest question, the only thesaurus I have used is just a dictionary of synonyms.
In what I call a "real" thesaurus, the book is split into two parts. The second half is an alphabetical index of words. For any word that carries multiple meanings or shades of meanings, each is listed as a separate subheading, followed by a numerical reference. The first half of the book is arranged numerically, and that's where you look up the words that might be used to convey exactly what you're looking for.
Example (from one of the smaller, pocket editions):
settle: establish 150
... be located 184
... come to rest 265
... subside 306
... decide 480, 609
... pay 807
-down: become stable 150
... locate oneself 184
So from the index we can see that the word "settle" can serve a number of different shades of meaning. From the list, you choose the one or two that are closest to what you want to say, and look those up. So, for "settle" in the sense of "decide," we find the following:
480: V
judge, conclude, opine; come to (or arrive at) a conclusion; ascertain; determine.
deduce, derive, gather, collect, infer.
estimate, form an estimate, appreciate, value, count, assess, rate, rank, account; regard, consider, think of, size up [
colloq.].
decide, settle; try, pronounce, rule; find, pass judgment, sentence, doom, decree; give (or deliver) judgment; adjudge, adjudicate; arbitrate, award; confirm.
review, comment, criticize; examine.
And that's all just from the first of two numerical references for "settle" in the sense of "decide." The dictionaries of synonyms just don't (and can't) convey the multitude of shades of meaning that the true thesaurus does.
Now ... if anyone is tempted to fire up Amazon and buy a "real" thesaurus ... get the 7th edition, not the 8th. There have been a LOT of complaints about the 8th edition. Basically, it seems that the 8th edition tried to save pages, so in the index they list only the key word and the numerical references, without telling you what shade(s) of meaning the numerical references relate to. Serious writers have been up in arms, and are pretty much in agreement that this makes the 8th edition functionally useless.
