What is Cool ?
Cool is (adj) 1. quite cold Blow on your soup to make it cool. It was hot on deck but cool down below. Wines should be stored in a cool cellar. It gets cool in the evenings in September. 2. not enthusiastic I got a cool reception when I arrived half an hour late. The board was quite cool towards the proposal. 3. calm The nurses remained cool and professional when dealing with all the accident victims. 4. fashionable, interesting a cool party It’s cool to wear white trainers. (NOTE: cooler – coolest)(verb) to make something cool; to become cool She boiled the jam for several hours and then put it aside to cool.(noun) 1. a colder area which is pleasant After the heat of the town centre, it is nice to sit in the cool of the garden. 2. the state of being calm As soon as the reporters started to ask her questions she lost her cool.
source: Easier English, Student Dictionary Upper Intermediate Level