or是甚麼??10分!!!!!!!

or (EXPLAIN)
conjunction
used to show that a word or phrase means the same as, or explains or limits or corrects, another word or phrase:

eg 1) Rosalind, or Roz to her friends, took the initiative.
eg 2) Things have been going quite well recently. Or they were, up until two days ago.
來源:http://dictionary.cambridge.org/define.asp?key=55796&dict=CALD

問題一: 我想問這個or是甚麼意思?
是yahoo字典中的解說:也就是說,換言之 嗎? (
http://hk.dictionary.yahoo.com/search.html?q=1&s=or)

問題二: 請翻譯eg1) , eg2) 的意思

問題三: She or I am a girl.這句子的文法對嗎?