The Grampian Mountains are situated in Scotland between the Central Lowlands and the Great Glen, forming the largest part of the Highlands. The name is of uncertain origin. It is first recorded by the Roman historian Tacitus in the form Mons Graupius as the site of a battle where Roman forces under Agricola defeated the native Caledonians in 83 AD. In this context it may have denoted a single mountain or a small mountain range. The application of the name Grampian Mountains to an extensive part of the Highlands began in the 16th century and may be based on a typoographical error (Mons Grampius for Mons Graupius).
James S. Patton has argued that the name of this street is derived not directly from the name of the Scottish mountain range, but rather from a boat: "At the mouth the Conswater (sic) river in the I860s a wooden vessel sat. She had been in commission at one time in the murky past. She served as a training ship for a large number of boys undergoing 'correction’. Her name was the Gibralter, (sic) ending her days as what may be called in naval terms, a hulk. The local boatmen and wildfowlers of Sydenham would take sightseers out to look at this once proud ship and they would gawk at the boys performing their duties. There are records of one of the poor little souls having fallen overboard and his body washing up on the shore. [During a storm] the ship was badly damaged, so much that she needed to be overhauled. During this time they changed her name to the Grampian. Here we can see the name of Grampian Avenue from Ballymacarrett." A few sidelights on the local history of the old townland, James S Patton (1980) - self publication.
However, the fact that the street was named at least three decades after the era of the boat and the existence of other streets in the neighbourhood forming a Scottish mountain theme (Nevis Avenue, Cheviot Avenue, Lomond Avenue) tends to cast doubt on this explanation.
"That the new street from Holywood Road to Grampian Avenue be named Grampian Street". (9th May 1900).