She is five years 'senior to' me. = She is 'senior to' me by five years. [=she is five years older than I am]
She is five years my 'senior'. = She is my 'senior' by five years. [=she is five years older than I am]
He recently became a 'senior' partner in the accounting/consulting firm.
(..) I'm going back. I'm going back to high school, Ned! No! No, no. No way. Your spirit guide would not waste transformation magic... ...on you reliving your senior year and going to prom. No. Ned, this is my chance to have my life over, but to do it right. - Wouldn't you, if you had the chance? - No. (..)2009 17 Again