Becasue we are consideing various profit transactins and 
loss transactions during a specified period.

Eg: profit on sale of assets
    Loss on sale of Assets.

Eventhough our objective of preparing p&L is to determine 
what is the profit or loss for the given period.Based on 
the above logic we are calling it as profit and loss 
account.

becase we are preparing p\l a\c so  there is a chance get to
loss to get profit in trading a\c there is a chance to loss
in p\l a\c

Actually Profit & Loss A/c is the part of Final A/c and 
in Profit & Loss A/c we record incomes and gains from all 
the sources as well as expenses and losses occured both, 
thats why it is termed as Profit & Loss A/c not Profit or 
Loss A/c.
    we find either Profit or Loss from the Profit & Loss 
A/c, yet we term it 'Profit & Loss A/c' because without 
comparison of incomes and expenses we can not find the 
actual or net profit or loss result. 
    If we term it as Profit or Loss A/c, we will be 
restricted to record only profit or loss that will not lead 
to the end result.