Calum sits next to 4 phonetic neighbors — Callum, Malcolm, and Calvin are the closest matches by sound. Most share Calum's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"dove"
"twin"
"son of the cloud"
"great, powerful"
"narrow water"
"from the isle"
"city of the moon"
"son of fire"
"from the place Brodie in Moray, Scotland"
"mind, intellect, spirit"
"supplanter, one who follows"
"spear ruler (from Gerald)"
"home ruler"
"fair warrior, white hero"
"dark warrior"
"supplanter's son"
"to rejoice, joyful"
"young warrior, free man"
"aspen tree, quaking poplar"
"from the hollow"
"from the crooked stream"
Similar sound: These names share phonetic patterns with Calum — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as Calum.
Rhythm: Calum is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.