In a dream it is a ruqba [a life-tenancy gift; wordplay on raqaba 'neck']. The neck may signify emancipation and ownership. If a slave sees an iron collar on his neck [text reads ghulam 'boy', likely ghull 'collar'], his bondage will continue; if his neck is freed, it signifies his emancipation.
Dream meaning · al-Nabulsi
Neck (nape) رقبة
Source: al-Nabulsi, Ta'tir al-Anam fi Ta'bir al-Manam, p. 129. English translation by iDreamBot. Quran verses: Quran.com, Saheeh International.