妹妹的英文是sisiter，缩写应该是sis。
解释：
sister 英[ˈsɪstə(r)] 美[ˈsɪstɚ]
例句
1.她把她妹妹带到我办公室。
She brought her sister to my office.
2.他把我妹妹介绍给他的同班同学。
He acquainted his classmate with my
sister.
3.海伦和她妹妹将轮流摆餐具准备开饭。
Helen and her sister will alternate in
setting the table.
4.你可能记得，她有一个小妹妹，那时只
有五岁。
As you may recall,she had a little
sister who waS five years old then.
5.他欺骗你，和你的妹妹在一起。
He cheats on you with your sister.
6.但他强调他的妹妹，对吧?
But he emphasizes the sister,right?
6.我小妹妹和我有一天去了那家商场，在
时装部一个摊位一个摊位地逛，直到我
们终于发现了那个摊位和想要的毛衣。
My little sister andI went in one day
and strolled from stand to stand in the
fashion department until we found the
right stand and the right sweater.
民辉窗帘布艺
