What does collapse mean?

to collapse = join together ?

you mean elements collapsing?

that means that their isn't enough room for two floats, and one falls underneath the other.

collapse = fall

I was searching "collapse html", but there is more under "collapse css". I just looked at 2 now (there is 14 when I searched contents):

http://www.w3.org/TR/CSS2/box.html#collapsing-margins

In CSS, the adjoining margins of two or more boxes (which might or might not be siblings) can combine to form a single margin. Margins that combine this way are said to collapse, and the resulting combined margin is called a collapsed margin.

http://www.w3.org/TR/CSS2/text.html#egbidiwscollapse

<ltr>A <rtl> B </rtl> C</ltr>

...where the <ltr> element represents a left-to-right embedding and the <rtl> element represents a right-to-left embedding, and assuming that the 'white-space' property is set to 'normal', the above processing model would result in the following:

- The space before the B ( ) would collapse with the space after the A ( ).
- The space before the C ( ) would collapse with the space after the B ( ).


= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

collapse = join together?
collapse = fall under?
collapse = overlap?
collapse = all the above?

so whats the problem