noun, noun which may take the genitive case particle 'no'
paternal line; father's side of the family
Refers to lineage or relatives on the father's side. Often used in genealogical or family contexts, contrasting with 母系 (maternal line).
See also: 母系
彼は父系の家系を調べている。
He is researching his paternal lineage.
父系の親戚が集まった。
Relatives from the father's side gathered.