This I am taking very common example.
Automation Test frame work is a framework have some set of 
rules and regulations. Automation scripts are done to 
reduce your rework manually. if you take QTP, we will write 
scripts in VB. We saved as .vbs file.We will create a 
folder called ATF(automation test frame work).we will 
create several folders in that ATF. 1.Recovery scenario 
folder to save .qrs files 2.Test results folders to save 
results from qtp 3. Test data folders where we take input 
for scripts eg: word file for modular framework 4. Scripts 
folders to save .vbs files etc., Now we have to write 
script for any function and add that .vbs file to scripts 
folder, if you have recovery scenario for that function, 
add that .qrs file into recovery scenario folder , if you 
want to take data to run the script, take data from test 
data folder and finally save the results of scripts to Test 
results folder. This is Automation framework where you 
segretated your work into folders and files automatically.
There are many frameworks you have:
1. modular framework
2. keyword framework
3. hybrid framework
4. datadriven framework and more..........

please comment me, if i am wrong?