A simple explanation:
In software development, the term "Framework" means a library that provides developers with pre-built templates and pre-written code for standard programming tasks.
The use of this type of framework is to accelerate the development workflow and apply best practices in a fluid and simple way.
You will find these frames in different languages, as an example:
JavaScript development frameworks:
AngularJs, ReactJs, VueJs, MeteorJs, EmberJs, NodeJs, etc.
Java development frameworks:
Spring, Struts, Hibernate, JSF (Java Server Faces), etc.
PHP development frameworks:
Laravel, Symfony, CodeIgniter, Zend, Yii, CakePHP. Slim, Phalcon, FuelPHP, etc.
Now there are some frameworks that are cataloged as cross-platform, such as:
Ionic
React Native
Flutter
What these frameworks have in common is that they are written in javascripts that, transpiling with the Android and IOS APIs, generate hybrid applications for mobile devices.
Regards.