Hi Vikas,
the Reference Manual is quite a good place to get all questions answered, especially the Glossary.
There you could read:
dimension:
A chart dimension is the set of values for the chart
to iterate over when it calculates the values for its
expression(s). In the simple case one could say
that it is what appears on the x-axis in a standard
bar chart. Normally a dimension consists of a field
but it may also be a group or a calculated expression.
expression:
A formula. Expressions can be used in a number
of places in QlikView: In the load script, in charts,
as dynamic labels, in text boxes, etc.
Regards,
Stefan
