In Turkish, there are specific names for people that are related to you, going beyond the simple aunt, uncle, grandmother, sister-in-law, etc. that I am used to in English.
Some are more commonly used than others, and the terms abi and amca (a man slightly older than you, a man quite a bit older than you) or abla and teyze (a woman slightly older than you, a woman quite a bit older than you) are respectful terms that can be used for anyone, not just a relative.
Often times the letter m is added to the end of a name to make it possessive, I refer to my host mom and dad as 'Annem' and 'Babam', meaning 'my mom' and 'my dad'.
Similarly to English, you can tack the whole word onto someone's name; I call my mom's sister 'Aunt Renee', or 'My Aunt Renee', in Turkish I would call her 'Renee Teyzem'.
Also a fair amount of these overlap; in the same way your brother's wife is also your sister-in-law. Which names are used casually or commonly probably varies from family to family, and in what context you are referring to the person. My cousin helped me come up with this list and had trouble thinking of some of the more obscure ones, he doesn't use or hear them too often.
Your mom is... anne
Your dad is... baba
Your sibling is... kardeş
Your younger brother is... erkek kardeş
Your younger sister is... kiz kardeş
Your older brother is... abi
Your older sister is... abla
Your mom's sister is... teyze
Your mom's brother is... dayı
Your dad's sister is... hala
Your dad's brother is... amca
A man related to you by marriage is... enişte
A woman related to you by marriage is... yenge
Any cousin is... kuzen
Your sister's husband is... bacanak
Your brother's wife is... elti
Your spouse's brother is... kayın
Your husband's sister is... görümce
Your wife's sister is... baldız
Your spouse's mom is... kayın anne (kayınanne)
Your spouse's dad is... kayın baba (kayınbaba)
On a side note,
Your best friend can be... kanka