Longman Dictionary of Contemporary English
directory enquiries
noun
EXAMPLES FROM CORPUS
▪ First he rang directory enquiries and then the operator.
▪ Only when she checked with directory enquiries did she learn that the receiver was off the hook.
▪ Pascoe had obtained the number from directory enquiries and listened to her answerphone message a dozen times or more.
▪ Perhaps she should get his number from directory enquiries.
▪ She hunted down the telephone number through directory enquiries and then rang.