"Rare" What Does It Mean?

"Rare" in the antiques industry - which very broadly includes coins - does have a technical meaning: something that is towards the higher end of the rarity scale. It is rarer than "scarce", but not as rare as "unique". It can have modifiers beyond basic "rare" eg. "very rare" and "extremely rare". Exactly how many identical items would fall into the "rare" category depends to a large extent on supply and demand. From the point of view of an Early American Cent collector, no Lincoln Cent, not even the 1909-S-VBD, would qualify as "rare", but from the point of view of a Lincoln Cent collector, the 1909-S-VDB certainly is "rare".

From the point of view of ebay, however, "Rare" (and its adjectivally extended versions) has been reduced to a meaningless attention-getting space filler, like "LQQK". To qualify as rare on ebay, it seems all you need is for it to not have a better than 50% chance of finding one in circulation this week.

On the general subject of rarity, it is linked to supply and demand - specifically, the "supply" side. "Supply" is essentially mintage multiplied by survival rate. It is usually proportional to mintage, but not necessarily so - the 1933 double eagle is an extreme example of rarity-mintage disconnect: it has a mintage of 445,000 which wouldn't see it classified as "rare" for that series - except we know that virtually the entire mintage was melted down before it was issued, making the original mintage figure effectively meaningless.

Sap pretty much makes the point. I will add that you must consider two forms of "rarity". First is absolute rarity which is largely defined by the total mintage and survival rate of a particular coin. Secondly would be condition rarity in which the population of even a common date coin may be almost impossible to acquire in a high grade or top pop.

"rare", by definition, just means "not occurring very often". Getting a Wheat cent in change is "rare".

"rare" on ebay frequently means seller wants you to think it is more valuable.

Right now, there are over 190,000 listings in the coins and paper money category described as "rare".

A "rare" 1943 Lincoln Cent because it is made of steel.
A "rare" bicentennial quarter.
A "rare" 1969 Roosevelt dime because it has no mint mark.
A "rare" 2016-D Presidential dollar.
A "rare" 2005-D Jefferson nickel.

also:
A "rare" 1899 $10 gold PR-67

"scarce", by definition, means "deficient in quantity or number compared with the demand : not plentiful or abundant".

A scarce item is often properly described as rare (occurs infrequently).
A rare item may not necessarily be scarce (a steel cent, for example).

Unfortunately, these two words are often used as if they were equivalent.

Thanks everyone. Yes Classic I have but most seem to be limited to certain times and places. I remember as a beginner (1950's) the first coin books I saw where in the public library and one of them did have a rarity scale in the intro. For world coins it was like Very rare = 20 pcs Rare = 100 pcs etc. Can't remember which book but I thought it was a good idea at the time.

I agree.
Here is the tdz rarity index:
Very rare - cannot find more than one sale of the coin in any of the normal places like acsearch in the last 20 years.
Rare - fewer than 5 sales

Nothng else deserves this adjective. The 1909SVDB is not rare, except by comparison to other Lincoln Cents, which is a myopic viewpoint.

And rarity should not be confused with selling price. Many, many coins exist which are rarer than the 1804 U.S. dollar. They just happen to not be as valuable (see here: http://goccf.com/t/428192 )

A coin is expensive if it has a lot of demand for it. Thousands of us want an 1804 Dollar or a $4 Stella or a 1933 Double Eagle the Feds wont haunt us for.

True rarity is a matter of count.

The keys to series, especially anything 1900s might be relatively expensive, but there are a few thousand of them floating around. There just happen to be enough people wanting them to keep values inflated.

On the flip side, my 382 AD dated Western Satraps coin with the ruler Simhasena has maybe 5ish specimens known. Its worth less than $1k because only a few nerd out in this realm.

The word "rare" doesn't mean anything to me unless I read it in a very reputable, scholarly work. As an advertisement, it's meaningless. I do care about the Sheldon scale and track the scarcity of my area of interest, capped bust Half Dimes by die marriage / remarriage, according to this scale. For many of the classic series, the R- numbers are estimated (or even known!) and it is very helpful. For more modern, plentiful, issues, this isn't particularly helpful. Even the famous 1909-s VDB cent had 484k minted - an "R-1" estimate, but still a key for the many Lincoln Cent aficionados. By contrast, there are only nine 1835 LM-12 capped bust Half Dimes - I counted 'em recently - and I've owned two of them. Supply and demand at work... :-)

Rarity Estimated Number in Present Existence
R-1 Greater than 1,250 specimens known
R-2 501 - 1,250
R-3 201 - 500
R-4 76 - 200
R-5 31 - 75
R-6 13 - 30
R-7 4 - 12
R-8 2 - 3
Unique 1 (sometimes aka R-9)