I wrote this one over the course of a few months that summarized everything I could think of on the topic - https://www.taniarascia.com/asynchronous-javascript-event-lo...
>Callbacks are not asynchronous by nature, but can be used for asynchronous purposes.
Glad you mention this because some people make it since like callbacks are a de-facto asynchronous-based concept. Callbacks are simply anonymous functions or lambdas that you pass to asynchronous functions so you can work with the produced values. Correct me if I'm wrong though.
Callbacks are anonymous functions [or references to named functions] that you pass to asynchronous [or synchronous] functions so you can work with the produced values [or do anything else]