n.
1.any specific activity
2.the state of being active
3.an organic process that takes place in the body
4.(chemistry) the capacity of a substance to take part in a chemical reaction
5.a process existing in or produced by nature (rather than by the intent of human beings)
6.the trait of being active
Idiom of the Day
quake in one's boots
to be afraid, to shake from fear
I was quaking in my boots when my boss told me to come to his office.