directory enquiries 
(North American directory assistance)
plural noun
A telephone service used to find out someone’s telephone number.192 was (until very recently) the telephone number for directory enquiries in the UK....
- In practice, that will mean dialing operator service numbers such as directory enquiries and voicemail facilities is the same, wherever you are and whatever language you speak.
- Context-specific, speaker-independent software is in common use today for 1-800 telephone directory assistance, flight reservations, and other uses.