How many letters does the top answer for “one related on the father's side” have?

The most common answer is agnate (6 letters).

Crossword clue: one related on the father's side

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

agnate 6 letters wn-def

one related on the father's side

related on the father's side 75% similar → agnate, agnatic

one related on the mother's side 60% similar → enate

on or to one side 50% similar → aside