From Longman Dictionary of Contemporary Englishseniorsenior1 ●●●W2 adjective1HIGH POSITION OR RANKhaving a higher position, level, or rank → juniorthe senior Democrat on the House committeeWhite men hold most of the jobs in senior management.the senior partner in a law firmsenior toHe is also a diplomat, but senior to me.2[only before noun] British EnglishOLD/NOT YOUNG a seniorcompetition is for older people or for people at a more advanced levelI won the 60-metre race, my first senior success.COLLOCATIONSnounssenior managementWithin the week senior management approved her proposal.senior staffSome senior staff criticized the headteacher's behaviour.a senior managerShe's now a senior manager for a large toy company.a senior executive (=in a company)All the company's senior executives get large bonuses.a senior official (=in an organization)a meeting of senior government officialsa senior officer (=in the police or military)Inspector Wild is the senior officer in charge of the investigation.a senior partner (=in a law firm etc)He was a senior partner in a prestigious Canadian law firm.a senior memberThe president announced a reshuffle involving several senior members of his Cabinet.
seniorsenior2 ●○○ noun [countable]1American EnglishSESSEC a student in their last year of high school or university → freshman, junior, sophomoreJen will be a senior this year.2OLD/NOT YOUNG especially American English a senior citizenSeniors can get a 10% discount.3 →be two/five/ten etc years somebody’s senior4British English an adult or a person who has reached an advanced level in a particular sport → juniorJuniors and seniors train together on Wednesdays.
Examples from the Corpus
senior• I took French when I was a senior.• Rossmoor was designed as a housing development for activeseniors.• The age-oriented community was conceived as a combination housing development and amusementpark for active seniors.• The entireseniorclass took a trip to Disneyworld.• The naturewalk is $ 9 for adults, $ 7 for seniors and kids 5 to 11.• My senior had not been a Humber.• I can't believe that Cari is a high school senior already.• And most of the seniors had not welcomed the appointment.SeniorSe·ni·or /ˈsiːniə $ -ər/ (written abbreviation Sr. American English, Snr British English)OLD/NOT YOUNGused after the name of a man who has the same name as his son → JuniorJohn J. Wallace, Sr.From Longman Business DictionarySeniorSe‧ni‧or /ˈsiːniə-ər/, written abbreviation Snr. American English, Snr British Englishused after a man’s name to show that he is the older of two men with the same name and from the same familyJohn Walker, Snr.seniorsenior1 adjective1having a high position in an organization, company etca panel ofsenior corporateexecutivesHe has held severalsenior management positions.Previously, he had been a senior partner (=the more important person in a business partnership) in a law firm.senior toStaff senior to the area supervisor play an active part in shaping the standards to be set.2[only before a noun]FINANCE senior lenders, SHAREHOLDERs etc have to be paid before other lenders etc if the borrower gets into financialdifficultyOnly after senior creditors were paid in full would ordinary shareholders get some cash.The group has agreed a plan with its senior lenders to restructure its credit facilities.3[only before a noun]FINANCE a company’s senior shares, bonds etc are considered to be more valuable because investors owning them will be paid before those owning ordinary shares, bonds etc. Those with senior shares etc will also be paid a larger percentage of what they are owed if the company gets into financial difficultyHalf of the purchase price was paid in cash and the balance insenior stock.seniorsenior2 noun [countable]JOBsomeone who has a higher rank than others in an organization or professionHe found it difficult to interest his seniors in the venture.