We'll learn some relation's name in Sanskrit, As in India unlike other languages we cherish each and every relationship and also take this earth as to be our family:

पिता (Pitā) - Father 

माता (Mātā) - Mother
पुत्रः / पुत्री (Putraḥ/ putrī) - Son/ Daughter
भ्रातृ (Bhrātr̥) - Brother
भगिनी (Bhaginī) - Sister
सहोदर:/ सहोदरा (Sahōdaraḥ/ Sahōdarā) - of the same womb
पितृव्य (Pitr̥vya) - Uncle (Father's brother)
पितृव्या (Pitr̥vyā) - Aunt (Father's brother's wife)
मातुलः (Mātulaḥ) - Maternal Uncle (Mother's brother)
मातुलानी (Mātulānī) - Maternal Aunt (wife of Mother's brother)
भागिनेयः (Bhāginēyaḥ) - Sister's son
पितामहः (Pitāmahaḥ) - Grandfather
पितामही (Pitāmahī) - Grandmother
पौत्रः (Pautraḥ) - Grandson (Son's son)
मातामहः (Mātāmahaḥ) - Maternal Grandfather (Mother's father)
मातामही (Mātāmahī) - Maternal Grandmother (Mother's mother)
दौहित्रः (Dauhitraḥ) - Daughter's son
पतिः (Patiḥ) - Husband
पत्नीं (Patnī) - Wife
स्नुषा (Snuṣā) - Daughter-in-law (Son's wife)
श्वशुर:(Śvaśuraḥ) - Father-in-law (Husband/ wife's father)
श्वश्रूः (Śvaśrūḥ) - Mother-in-law (Husband/ wife's mother)
देवरः (Dēvaraḥ) - Husband's brother
भ्रातृजाया (Bhrātr̥jāyā) - Brother's wife
याता (Yātā) - Husband's brother's wife
आवुत्तः (Āvuttaḥ) - Brother/ Sister's husband
श्यालः (Śyālaḥ) - Brother-in-law
ननान्दा (Nanāndā) - Sister-in-law

Happy Learning !