What is a good icon for illustrating expand (and collapse) all? [closed]

Go with a chevron. It is widely used for collapsing and expanding, and it's rather self explanatory.

1. What is the expand collapse button?
2. What are the symbols seen while collapsing and expanding the folder in Windows Explorer?
3. What is the expand arrow called?
4. What is collapse in web design?

What is the expand collapse button?

This pattern creates a button that toggles an element as hidden (collapsed) or not hidden (expanded). The element's current state and changes in the element's state are communicated to screen reader users.

What are the symbols seen while collapsing and expanding the folder in Windows Explorer?

Expand/collapse symbols (+/-) appear next to folders that contain subfolders. A plus (+) symbol means that the folder is collapsed and the subfolders are hidden in the folder tree. A minus (-) symbol means that the folder is expanded and the subfolders appear in the folder tree.

What is the expand arrow called?

It's a tree view widget known as an expander arrow.

What is collapse in web design?

)To compress a view of a hierarchy so that only the roots of each branch are visible. The opposite of collapse is expand, which makes the entire branch visible. Webopedia Staff. Since 1995, more than 100 tech experts and researchers have kept Webopedia's definitions, articles, and study guides up to date.