Meaning of 姉ちゃん in Japanese

なるべく姉ちゃんにも周りにも迷惑をかけずに、事態の早期解決をなんとか頼むぞ。
I want you to somehow resolve the situation as promptly and avoiding to cause trouble for my sister and those around us as much as possible.

私はお姉ちゃんの夕飯をラップに包んでしまわないと。
I have to wrap my sister's dinner in clingfilm.

ママ〜！あのお姉ちゃんとお兄ちゃん、お手手繋いで、すっごく仲良しさんだね〜！
Mama! That lady and man are holding hands, they're great friends aren't they!