From Scottish

The name Arran does not have a widely documented traditional etymology in standard name references. It appears to be a modern, phonetic, creative, or uncommon spelling rather than a name with one established ancient meaning. For SEO or naming data, the safest full meaning is to describe Arran as a distinctive modern name; if it resembles a known root name, its meaning should be traced through that root rather than invented. This approach avoids assigning unsupported historical or linguistic claims.