Coin vs Geocoin - What's the difference?

As a proper noun coin

is a city in iowa.

a coin minted for use as a prize in geocaching, sometimes trackable on the internet by its serial number.

(en noun)

(money) A piece of currency, usually metallic and in the shape of a disc, but sometimes polygonal, or with a hole in the middle.

* 1883: (Robert Louis Stevenson), (Treasure Island)

...the coins were of all countries and sizes - doubloons, and louis d'ors, and guineas, and pieces of eight...

A token used in a special establishment like a casino (also called a chip).

(figurative) That which serves for payment or recompense.

* Hammond

The loss of present advantage to flesh and blood is repaid in a nobler coin .

One of the suits of minor arcana in tarot, or a card of that suit.

A quoin; a corner or external angle; a wedge.

* coinage

(en verb)

To make of a definite fineness, and convert into coins, as a mass of metal; to mint; to manufacture.

to coin''' silver dollars; to '''coin a medal

To make or fabricate; to invent; to originate.

Over the last century the advance in science has led to many new words being coined .

* Dryden

Some tale, some new pretense, he daily coined , / To soothe his sister and delude her mind.

To acquire rapidly, as money; to make.

* John Locke

Tenants cannot coin rent just at quarter day.

(en noun) (wikipedia geocoin)

A coin minted for use as a prize in geocaching, sometimes trackable on the Internet by its serial number.

* 2007 , Stan Spector, Baby Boomers' Official Guide to Retirement Income

Make a geocoin for their event so participants will have a collectible from the event.