coolˈant noun

1. A cooling agent
2. A fluid used to cool the edge of a cutting tool (engineering)
3. A fluid used as the cooling medium in an engine (engineering)
4. The gas or liquid circulated through a reactor core to carry the heat generated in it to boilers or heat exchangers

coolˈer noun

1. Anything that cools
2. A vessel in which something is cooled
3. A cool box or bag
4. A spritzer with additional fruit juice
5. Jail, esp a military jail (slang)
6. A refrigerator (N American)

coolˈish adjective

Somewhat cool

coolˈly adverb

1. In a cool manner
2. With composure
3. Indifferently
4. Impudently

coolˈness noun

1. Moderate cold
2. Indifference
3. Diminution of friendship
4. Lack of zeal
5. Lack of agitation
6. Self-possession

coolth noun (dialect)

Coolness

coolˈy adjective (Spenser)

Cool

cool box or cool bag noun

An insulated box or bag, used to keep food, etc cool

cool change noun (Aust)

A change in wind direction resulting in cooler weather

coolˈheaded adjective

1. Not easily excited
2. Capable of acting with composure

coolˈhouse noun

A greenhouse kept at a cool temperature

coolˈhunter noun (informal)

A person who studies and advises on probable trends in fashion

cooling card noun (Shakespeare)

Anything that discourages, or dashes hopes

cooling-off see cool off below.

cooling-off period noun

The time, usu a period of five to seven days, in which a consumer has the right to serve notice of cancellation of a credit, insurance, etc agreement

cooling tower noun

A large structure in which water heated in an industrial process is cooled for re-use

coolˈ-tankard noun

1. An old name for a cooler with spices and borage
2. A local name for borage

cool it (slang; often imperative)

To calm down, act in a relaxed fashion

cool off

1. To become less angry and more amenable to reason (cooling-offˈ noun and adjective)
2. To grow less passionate (coolˈing-offˈ noun and adjective)

cool one's heels

To be kept waiting

keep one's cool (informal)

To remain calm, keep one's head

lose one's cool (informal)

To become flustered

play it cool

To act in a deliberately controlled and calm manner