entropy (the word)

can someone explain to me what this word means?
I dont need to know my sis her boyfriend needs to know

1)Symbol S For a closed thermodynamic system, a quantitative measure of the amount of thermal energy not available to do work.

2)A measure of the disorder or randomness in a closed system.

3)A measure of the loss of information in a transmitted message.

4) The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity.

5)Inevitable and steady deterioration of a system or society.

in other words:
http://dictionary.reference.com/search?q=entropy

la la la.
sounds confusing.

Just had to ask this:
Cermie, why does the 50% of your posts start with "la la la"? 😛