OWASP (Open Web Application Security Project) is a non-profit organisation and online community dedicated to providing open-source solutions to help build secure web applications. Further reading OWASP Top Ten

Patching is a process in software development and ongoing maintenance where updates are applied to software to fix problems with the original code such as fixing vulnerabilities, improving functionality, or to enhance performance and speed. These updates, known as patches, are essential for maintaining the security and efficiency of software systems. Further reading Patching - Wikipedia

Paul Graham’s Essays Start with How to do great work

Penetration testing (or pen testing) is a security exercise where a cyber-security expert attempts to find and exploit vulnerabilities in a computer system. The purpose of this simulated attack is to identify any weak spots in a system’s defenses which attackers could take advantage of. This is like a bank hiring someone to dress as a burglar and try to break into their building and gain access to the vault. If the ‘burglar’ succeeds and gets into the bank or the vault, the bank will gain valuable information on how they need to tighten their security measures. ...

Further reading Permacomputing wiki - introduction