Dennis sits next to 4 phonetic neighbors — Denis, Denny, and Dean are the closest matches by sound. Most share Dennis's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"follower of Dionysus"
"great tide, son of the sea"
"son of Nicholas, son of Nick"
"ruler of the people"
"God will uplift (from Jeremy/Jeremiah)"
"God is gracious"
"counsel + wolf (rád + ulfr)"
"path, track, trail"
"land of Eoghan (short for Tyrone)"
"son of Walter"
"lion-like, brave"
"protector of mankind"
"son of Edie (son of Edward)"
"God's darling"
"leader, commander (variant interpretation)"
"brave in power"
"beam of light"
"white/pale (from Cas people)"
"God is my help"
"brook, small stream"
"name of God"
Similar sound: These names share phonetic patterns with Dennis — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek origins, giving them the same cultural heritage as Dennis.
Rhythm: Dennis is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.