Core Services are a set of Mac OS X and iOS application programming interfaces that architecturally are underneath Carbon, Cocoa and Cocoa Touch. In addition to Core Foundation, it also encompasses other APIs including Grand Central Dispatch, Blocks, CFNetwork, CarbonCore, OSServices, and WebServicesCore.

A core network, or network core, is the central part of a telecommunications network that provides various services to customers who are connected by the access network. One of the main functions is to route telephone calls across the PSTN.