prefix
great- (kinship prefix)
Prefix attached to kinship terms to indicate a generation two steps removed, e.g., 曾祖父 (great-grandfather), 曾孫 (great-grandchild). The reading ひい is the most common; ひ is a shortened form used in some compounds, and そう is a Sino-Japanese reading used in formal or written contexts.
曾祖父は明治時代に生まれました。
My great-grandfather was born in the Meiji period.
彼女は曾孫に会うのを楽しみにしている。
She is looking forward to meeting her great-grandchild.
Variant kanji form; less common than 曾 but still encountered.
The prefix 曾 (ひい) is of native Japanese origin, used to indicate a relationship two generations removed. The kanji 曾 and 曽 are Chinese characters adopted for their meaning 'great-' in kinship terms. The reading そう is the Sino-Japanese on'yomi.