Kingdom sits next to 3 phonetic neighbors — Kingston, Kingsley, and Kinston are the closest matches by sound. Most share Kingdom's Old English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"realm, dominion"
"third"
"bright, shining, evident"
"varies by given names the initials represent"
"son of Jacob"
"appointed by God"
"from the city of Troy"
"Yahweh has saved"
"powerful, compassionate (fictional origin)"
"rejoice, be glad (via Gaius/Caio)"
"talent, ability, brilliance"
"joy, song of joy"
"new town"
"son of Morris/Maurice"
"to carry, to bear"
"precious gem, jewel"
"little king"
"friend of the gods (Germanic tradition)"
"father of peace"
"descendant of Ógán"
"steward, household manager"
Similar sound: These names share phonetic patterns with Kingdom — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Kingdom.
Rhythm: Kingdom is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.