As per Wikipedia definition, Netcat is a general-purpose command-line tool for reading, writing, redirecting, and encrypting data across a network. It aims to be your network Swiss Army knife, handling a wide variety of security testing and administration tasks. Netcat is suitable for interactive use or as a network-connected back end for other tools.
Reading more in
https://www.hackingtutorials.org/networking/hacking-with-netcat-part-1-the-basics/
Cyber Security: Awareness is the key 