There are many kinship terms in Hindi (i.e. words that describe family relationships), since there is almost one word per relationship. Some of the most common terms are listed below.
Key: blue = male, pink = female, yellow = you, “stacked” boxes = marriage, lines = children; generations are approximately parallel
Mother: ममी (जी); The English term “mummy” is most common, and it may be suffixed with जी for respect. The formal Hindi word is माता (जी), but this is seldom used, just as one would seldom address one’s mother as “mother” in English.
Father: पापा (जी); The English term “papa” is most common, and it may be suffixed with जी for respect. The formal Hindi word is पिता (जी), but this is seldom used, just as one would seldom address one’s father as “father” in English.
Sister: बहन / बहिन; An elder sister is called दीदी. Female cousins are informally called बहन/दीदी too.
Brother: भाई; male cousins are also informally called भाई / भैया. An unrelated male peer may be addressed as भैया.
Cousins are typically addressed by name, or by using the same terms for “brother” and “sister”.
Wife: पत्नी / बीवी
Father’s Father (Grandfather): दादा (जी), बाबा (जी)
Father’s Mother (Grandmother): दादी (जी)
Father’s Elder Brother: ताऊ / ताया; Wife: ताई
Father’s Younger Brother: चाचा; Wife: चाची
Father’s Sister: बुआ / फूफी; Husband: फूफा
Mother’s Father (Grandfather): नाना (जी)
Mother’s Mother (Grandmother): नानी (जी)
Mother’s Brother: मामा; Wife: मामी
Mother’s Sister: मौसी; Husband: मौसा
Husband’s Father: ससुर
Husband’s Mother: सास
Husband’s Elder Brother: जेठ; Wife: जेठानी
Husband’s Younger Brother: देवर; Wife: देवरानी
Husband’s Sister: ननद; Husband: ननदोई
Wife’s Father: ससुर
Wife’s Mother: सास
Wife’s Brother: साला
Wife’s Sister: साली
Brother’s Wife: भाभी
Brother’s Son: भतीजा
Brother’s Daughter: भतीजी
Sister’s Husband: जीजा
Sister’s Son: भांजा
Sister’s Daughter: भांजी
Son’s Wife: बहू
Son’s Son: पोता
Son’s Daughter: पोती
Daughter’s Husband: दामाद
Daughter’s Son: नाती
Daughter’s Daughter: नतिनी (or नातिन)
The suffix जी is often used to show respect. The words छोटा/छोटी and बड़ा/बड़ी can be used to talk about a “little” or “big” sister, or an elder or younger uncle, etc.