If you would like to know the answer to the question, "What is twill?".  You may want to read the what is twill? page on WiseGeek.  Another helpful tool for learning about twill would be to read the Twill Fabric Definition on Wikipedia.  Here are a few more resources to help with your research:

Twill - from Anwers.com
Twill Definition - from the FreeDictionary.com website.
Tips on Choosing Twill Fabric - from Essortment.com

Twill categories listed on WiseGeek:

Twill 

Twill Material 

Twill Clothing 

White Twill 

Twill Denim 

Twill Skirts 

Twill Pants 

Here are some textile guides that may be of further assistance:

Wholesale Fabric 
Fabric Stores

If you have suggestions regarding additional resources that should be added to this section, please do not hesitate to let us know.  It would be our pleasure to add helpful information to make this area of our guide more informative.

 

We hope that this section has helped with your research of Twill Fabric.