> Is there a practical distinction? I’m not sure if this will help, but I think of it like - parallelism is running the same task in multiple threads / on mult

> Is there a practical distinction? I’m not sure if this will help, but I think of it like - parallelism is running the same task in multiple threads / on multiple cores at once. And concurrency is “concurrently” running different tasks on one core. Nodejs is a purely single threaded runtime. Let’s say you have a web server in node processing http requests. - Your program implements concurrency by yielding back to the event loop instead of blocking. Request 1 comes in, and then sends a query to the database. While we wait for the database to respond to the query, we can process request 2. - You usually implement parallelism with nodejs by running multiple instances of your nodejs server process across all your cores. (Then use a program like nginx to load balance requests across all the node processes.) The GPU might be a better example. When rendering a frame, the graphics card runs a small program (called a fragment shader) for every pixel on the screen. A 4090 has ~16000 cores which can all run the same fragment shader on different pixels at the same time. This is called parallelism, not concurrency. Concurrency would be if you had two video games open at once and your graphics card was quickly swapping between rendering frames for game A and game B.