Spool up...

[south coast]

Could someone please give me the definition of spool up.

Is it when the engine is accelerated from an idle power setting to a power setting where thrust is being developed?

And, if you are in the cruise at a particular epr setting and need to set max thrust, which is say 0.4 epr above the cruise, (made up values) could that acceleration of the engine be considered 'spool up'?

thanks