According to
Genesis 17:15, God changes her name from
Sarai to Sara(h).
In the (Greek) Septuagint, the change is from
SARA to
SARRA.
Some scholars take this as an argument against the common theory, that both names have the same root.
I have never heard of the meaning "contentious," as this site claims (I can't find a similar word in my Hebrew dictionaries), but maybe this interpretation follows the same idea as what I read some place:
SARAI is connected with Arabic "shara," sparkling, possibly referring to the eyes.