姥爷
lǎo ye · HSK 7
maternal grandfather (dialectal)
👴 姥爷 = 姥 (maternal side, 女 woman + 老 old) + 爷 (grandpa) = mom's dad
爷 (ye) is the standard word for grandpa or sir; 姥 carries the 女 woman radical to mark the maternal side. Together they name mom's father, a usage common in northern dialects.