Need help on Income Tax's terminologies

Dear All,

I would like to know the meaning and info on the following terminologies :

Dearness Pay

Dearness Allowance

Fees

Commission

Bonus

Gratuity

Pension

RPF and different types of PF’s

If possible is it possible to get any link to download e-book related to income tax too???

Thanks in advance,

Commission - Clause (ii) of sub-section (1) n The expression ‘commission’ has no technical meaning but both in legal and commercial acceptation of the term it has definite signification and is understood as an allowance for service or labour in discharging certain duties, such for instance, of an agent, factor, broker or any other person who manages the affairs or undertakes to do some work or renders some service to another. Mostly it is a percentage on price or value or upon the amount of money involved in any transaction of sale or service or the quantum of work involved in a transaction. It can be for a variety of services and is of the nature of recompense or reward for such services - Harihar Cotton Pressing Factory v. CIT [1960] 39 ITR 594 (Bom.). n The word ‘commission’ in this clause should be interpreted ejusdem generis with the word ‘bonus’. - Raja Ram Kumar Bhargava v. CIT [1963] 47 ITR 680 (All.).