The word itself comes from the Latin word “senior”, which is a comparative adjective meaning older and its use in Spanish has recently been amplified as a result of its use in English. In Spanish, it should always have the accent on the “e”, since it ends in a consonant other than “n” or “s”.
Today it is used with a few different meanings:
a) After the proper name of a person in order to distinguish him from a younger relative with the same name, generally the son.
b) In sports, to describe “an athlete of a higher level, whether it is the result of age or achievements”.
c) When speaking about employees, to refer to “an older professional who has more experience than another”. At times it is used for higher-level employees, regardless of their age.
Even though the Anglicism “séniors” is often found for the plural, it is incorrect. Instead, it is recommended to adapt Spanish spelling rules and use “séniores”.