dynamic libraries on macOS are dylibs. There is a debate whether 'ld' is short for load/loader, or link editor. So you can either read it as the dynamic library

dynamic libraries on macOS are dylibs. There is a debate whether 'ld' is short for load/loader, or link editor. So you can either read it as the dynamic library load tool or the dynamic link editor. A shared dyld cache would be a cache of metadata used for linking, but not sure if that is for link-time or runtime.