December sits next to 4 phonetic neighbors — Ember, Amber, and December are the closest matches by sound. Most share December's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"tenth month (in original Roman calendar)"
"born on Monday (Hausa day-name)"
"devotee of battle rule"
"invented modern name, lady of the hills"
"eternal life, vitality"
"ancestors descendants"
"calm, gentle waters"
"bird, sun"
"princess, born of royalty"
"noble kind, of noble birth"
"night beauty"
"light-bringer (when used as Lucia variant)"
"beauty, loveliness"
"divine life force from the sky"
"grassy island"
"flowing waters"
"little love, sweetheart"
"entire, all-encompassing"
"twin"
"graceful, favored (from Ana/Hannah)"
"strong, enduring"
Similar sound: These names share phonetic patterns with December — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Latin origins, giving them the same cultural heritage as December.
Rhythm: December is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.