An entry point is the code path a Node.js package exposes when another program imports it or runs it directly. In practice, this is usually controlled by fields such as main or exports, which tell Node.js which file should load first and which functions or modules are available to callers.
This matters in cyber security because malicious behavior can hide in ordinary package logic instead of install-time scripts. A dependency may look harmless during installation, then trigger unwanted actions only when its exported code is used at runtime. Defenders review entry points to understand what code actually executes, limit trust in lookalike packages, and test the functions that applications really call. Checking only install hooks is not enough when the risky behavior lives behind the package’s public interface.