<P> Words for family members have two different forms in Japanese . When referring to one's own family members while speaking to a non-family - member, neutral, descriptive nouns are used, such as haha (母) for "mother" and ani (兄) for "older brother". When addressing one's own family members or addressing or referring to someone else's family members, honorific forms are used . Using the suffix - san, as is most common, "mother" becomes okāsan (お母さん) and "older brother" becomes oniisan (お 兄さん). The honorifics - chan and - sama may also be used instead of - san, to express a higher level of closeness or reverence, respectively . </P> <P> The general rule is that a younger family member (e.g., a young brother) addresses an older family member (e.g., a big brother) using an honorific form, while the older family member calls the younger one only by name . </P> <P> The honorific forms are: </P> <Ul> <Li> Otōsan (お父さん): father . The descriptive noun is chichi (父). <Ul> <Li> Ojisan (叔父さん / 小 父さん / 伯父 さん): uncle, or also "middle - aged gentleman". </Li> <Li> Ojiisan (お祖父さん / 御 爺さん / お爺さん / 御 祖父 さん): grandfather, or also "male senior - citizen". </Li> </Ul> </Li> <Li> Okāsan (お母さん): mother . The descriptive noun is haha (母). <Ul> <Li> Obasan (伯母 さん / 小 母さん / 叔母さん): aunt, or also "middle - aged lady". </Li> <Li> Obāsan (お祖母さん / 御 祖母 さん / 御 婆さん / お婆さん): grandmother, or also "female senior - citizen". </Li> </Ul> </Li> <Li> Oniisan (お 兄さん): big brother, or also "a young gentleman". The descriptive noun is ani (兄). </Li> <Li> Onēsan (お 姉さん): big sister, or also "a young lady". The descriptive noun is ane (姉). </Li> </Ul>

What's the difference between san and sama