Other forms: seniors
Senior means higher in rank, or older. A senior manager, senior staff, senior to me by three years.
Like junior, it takes to and never than — senior to him, not senior than him — because it is already a Latin comparative. In Britain a senior school is secondary; in America a senior is a final-year student and seniors also means older people generally, as in senior citizens. Note Senior after a name, abbreviated Sr, meaning the father of somebody with the same name. And seniority means length of service, which is what promotions are often argued about.
1adjectiveseniorHigher in rank or position.
“The decision was taken at a more senior level.”
synonyms: higher-ranking, superior
2adjectiveolderOlder.
“Senior citizens can travel on the buses for free.”
3nounfinalAn older person, or a final-year student.
“There is a discount for seniors on weekdays.”
Too few real examples of this word to estimate which sense is commonest.
senior is a rank or age relation.
Latin senior is the comparative of senex, old — the same root as senate, which was a council of elders, and senile. English took the comparative form and then had to invent seniority for the noun.
Proto-Indo-European
*sénos
Latin
senior — older
Middle English
senior
English, today
senior
Built from
From Middle English senior, from Latin senior (“older”), comparative form of senex (“old”); see senate. a doublet of seigneur and seignior and senhor and señor and senyor and signore and sir and sire.
Etymology from Wiktionary, CC BY-SA