/
ˈsiːnɪə, 
ˈsiːnjə/
adj.
   - for or denoting older people. ▸Brit. for or denoting schoolchildren above a certain age, typically eleven. ▸US of the final year at a university or high school. 
- 
[postpos.]
 denoting the elder of two with the same name in a family.
- high or higher in rank or status.
n.
    - a person who is a specified number of years older than someone else:![]()  she was two years his senior. 
- a student in one of the higher forms of a senior school.
- (in sport) a competitor of above a certain age or of the highest status.
- an elderly person, especially an old-age pensioner.
Derivative
Etymology
ME: from L., lit. ‘older, older man’, compar. of senex, sen- ‘old man, old’.