The term framework is widely used in today’s programming world. Framework is the layered structure which aids for rapid development since it provides the set of features and functionalities which will assist the developers to minimize their work for carrying out the basic functionalities. It is kind of collections of predefined reusable components which can be used to accomplish different features and its implementation.
There are different frameworks dedicated to their own programming language such as JAVA, PHP, CSS etc. Just to name like bootstrap, foundation are good framework for CSS which has been used globally for creating beautiful web applications. Similarly, frameworks like Spring, Struts are commonly used for JAVA development environment.
Not to be surprised there are many framework for WordPress theme development as well. Some of them are as below:
Underscores : Framework or Starter theme ?
I know guys i have missed some as well 🙂 but for me i think these are the good ones.
However the question arises about Underscores. Is it framework ?
Actually to answer, Underscores is a starter theme. It is meant to be worked with, tweaked, and styled. It is not a framework or a parent theme to be extended. It is supposed to become a theme of its own, when finished.
Underscore has also introduce the components, think of it as a toolbox for taking your themes where you want them to go, faster.
More details : http://components.underscores.me/
So it is important to choose the best framework which suits your need so that you can minimize the development hours. With my experience, most used and better framework is Genesis Framework due to its lightweight and clean coding although it is commercial and licensed and other not too forget, Underscores which is perfect to build any themes.