As an Adjective: A feminine adjective from the old Gaelic, meaning "star-like" or "connected to/from the stars." This may refer to astronomical bodies or astrological signs.
A sterrin is an amazing woman who exists in a world that doesn't fully understand her. She is given to excitement and romance, but like a comet she passes thru but is rarely affected by other bodies' influence. Like a comet, she is free and fills observers with awe! But like a comet, she feels doomed to forever wander.
Her mystical tendencies are romantic in nature, and her heart is so big that she rarely thinks of herself. She is mostly unaware of her inspiring effects on others. But she is acutely aware of the struggles of her admirers and wishes to be a part of the worlds she passes by.

As a Noun: An amazingly mystical beauty

When you eat dirt for the first time and leave your family to build a shack in the woods