A privacy coin is a type of cryptocurrency that use technology to make it very difficult to link an individual to a transaction providing anonymity to parties involved and confidentiality of deals of the transaction like the amount.

Contrary to popular belief, most cryptocurrencies including Bitcoin do not provide anonymity. As partbof its design, transactions that are recorded on a blockchain are public.

Transactions occur between wallet addresses (which are just a string of letters amd numbers linked to your crypto wallet.)

Depending on cryptocurrency, the information recoderd on the blockchain can include details like sender's and recipient's wallet addresses and the transaction amount. 

For example,  whenever a Bitcoin transaction happens, everyone and their mamas can see that the ownership of BTC has moved from one Bitcoin address to another Bitcoin address. 

So, privacy coins, also known as private coins, or anonymous coins, are cryptocurrencies that hide any information that can link an individual to a transaction, and other information such as the amount transacted, and current balances of wallet addresses. 

For example,  the buyer and sender of a transaction will know the amount transacted and the parties involved (themselves), but same information will be unavailable to anybody else.

This allow users to maintain their anonymity and hide their transaction activity. In order to be completely anonymous,  it has to be impossible to link the different transactions that were done by the same person.

Not all privacy coins provide the same level of privacy and vary in their degree of anonymity.