800 number 
/ˌeɪtˈhʌndrəd-/ noun
plural ∼ -bers /ˌeɪtˈhʌndrəd-/ noun [count] US : a telephone number that people can use to call a distant place (such as a business) for free ◊In the U.S. 800 numbers usually have 800 as an area code.
▪ Call our 800 number to place an order or ask questions.
▪ Call our 800 number to place an order or ask questions.
