Framework is more of testapproach to be followed for 
automation test process like the type of framework
(keyword,Functional,Hybrid etc), reusable components and 
actions,libraries etc. It also covers the coding standards,
test reporting process.

framework means set of assumptions the we take to test the 
application.

Test automation frame work is a set of assumptions, 
concepts and practices that provide/constitute a work 
platform or support to automated testing.

Framework is necessary to identify how we are going to 
automate the test. A framework in place gives better 
understanding and visibility to how much progress we have 
made in terms of the project and better management and 
minimize the amount of work and time required for the 
maintenance of the automation project in case of updates or 
modification required at any later stages of the life cycle.

We follow the Hybrid framework where we use the Test Script 
modularity, Test Library architecture and Data Driven 
framework,Table Driven/Keyword Driven framework (Tool: 
Rational Robot)

Test Script Modularity FW: is nothing but creating small 
independent scripts that represents modules, Scenarios or 
functions of the AUT. are inturn used in a heirarchical 
fashion to form larger tests.

Test library architecture:  is using of library files
(dll's, API's,VBS files which your tool supports) in your 
automation test.

Keyword  Driven or Table driven: is creating tables based 
on the AUT's Window, Objects, Action performed on that 
object and the data supplied to it. Once the table is 
created for the test, write a program or scripts that 
represent each step in the tale. Nothig but descriptive 
programming.

Data Driven framework is notng but using of Data Pools
(Rational robot), Data Driven test in Winrunner and QTP.

Hybrid FW: is nothing but a combination of all of or any of 
the above mentioned framework.

With Rational Robot we were using hybrid framework