What does error code 137 specifically mean in the context of Minecraft?

Error code 137 in Minecraft typically indicates that the game process was terminated by the operating system due to insufficient memory. It's not a Java crash but rather an OS-level signal (SIGKILL, exit code 128 + 9) that occurs when the system forcibly shuts down the Java Virtual Machine (JVM) running Minecraft because it tried to allocate more RAM than was available or permitted, to prevent system instability. This is common when playing modded Minecraft or on systems with limited RAM.