The phrase "Rock of Gibraltar" has become synonymous with strength and stability. It is often used to refer to something that is unshakeable or immovable. However, there are several other phrases that can be used as a synonym for this famous rock.
One such phrase is "pillar of strength." This phrase implies that the object in question is a support system upon which others can rely. Another synonym for the rock of Gibraltar is "cornerstone." This term suggests that the object is central or foundational to a larger structure or system.
Finally, the phrase "bedrock" is also used to describe something that is immovable and unshakeable. This term refers to the solid rock that lies beneath the earth's surface, suggesting that the object in question is as solid as this natural formation.