/ ˌrɒk əv dʒɪˈbrɔːltə(r); NAmE / noun
[ sing. ] a high cliff in southern Spain, at the south-western edge of the Mediterranean Sea, near the town and port of Gibraltar. When people say that sth is like the Rock of Gibraltar, they mean it is very safe or solid :
When I invested my money with the company I was told it was as safe as the Rock of Gibraltar.