When crypto users say "pseudonymity," they are referring to the practice of using a pseudonym or fake name instead of one's real name when engaging in cryptocurrency transactions or other activities.
In a pseudonymous system, users are not required to reveal their real identities to use the network, but they are still able to be identified by a unique identifier, such as a public key or an account number. This allows for some degree of anonymity, as the user's real identity is not tied directly to their actions on the network, but it is not complete anonymity, as the user's actions can still be traced back to their unique identifier.
Pseudonymity is a key feature of many cryptocurrencies, including Bitcoin and Ethereum, as it allows users to maintain a level of privacy while using the network. However, it is important to note that even in a pseudonymous system, users may still be vulnerable to various forms of surveillance or tracking, so it is not a foolproof way to maintain anonymity.