a.m.
a.m. — adverb
1. written after a number to show the time is in the morning, from twelve o'clock a
written after a number to show the time is in the morning, from twelve o'clock at night to twelve o'clock at midday.
The train for Taipei leaves at 6:30 a.m. every morning.
a.m. after the time in schedules
The first class starts at 8:00 a.m., so the children arrive before the bell.
a.m. for school and daily routines
The bakery opens at 5:00 a.m. to sell fresh bread.
Our flight from Tokyo landed at 11:45 a.m. local time.
The doctor's appointment is at 9:15 a.m. on Thursday.
- p.m.
refers to the afternoon and evening, from midday to midnight
用法筆記
Always placed after the time number (e.g., 7:30 a.m.). 12:00 a.m. is midnight, not midday — that is 12:00 p.m.
常見錯誤
a.m. — noun
1. a system for transmitting radio sound by varying the strength of the signal — us
a system for transmitting radio sound by varying the strength of the signal — used mainly by stations that focus on talk programmes, news, and sports commentary rather than music
The taxi driver listens to a traffic report on AM every morning.
collocation: on AM / AM station / AM radio
The old radio in the basement could still pick up AM news stations from three states away.
The emergency broadcast system uses AM signals to reach rural areas across the state.
Radio station WZYX switched from FM to AM in 2015 to reduce operating costs.
Sports fans in the stadium tune to the AM channel for live play-by-play commentary.
- MW
medium wave — a closely related broadcast band that largely overlaps with AM in many regions, though the two terms describe different aspects of the signal
- FM
frequency modulation — a different broadcasting method that produces higher sound quality but has a shorter range
用法筆記
In modern broadcasting contexts, this abbreviation is nearly always written AM without periods to distinguish it from the time abbreviation a.m. The full form 'amplitude modulation' is rare outside technical writing.
常見錯誤
2. an elected politician who serves in the Senedd (the Welsh Parliament in Cardiff)
an elected politician who serves in the Senedd (the Welsh Parliament in Cardiff) and is responsible for making laws and representing the people of a specific local district in Wales — distinct from other 'AM' abbreviations used for American nationality or airmail
The AM for Cardiff West held a public meeting about school funding last week.
AM for [constituency] — the pattern for referring to a specific member
Residents wrote to their local AM to express concern about the hospital closure plans.
Three new AMs were elected to represent constituencies in North Wales.
The Assembly Member introduced a bill to improve rural bus services across Wales.
As an AM representing the Swansea Valley, she works with community groups to secure Welsh government funding for local youth programmes.
- MS
Member of the Senedd — the newer official title introduced after the 2020 renaming of the Welsh Parliament
- Assembly Member
the full form of the abbreviation, more common in official documents and formal speeches
用法筆記
The abbreviation AM is specific to the Senedd Cymru (Welsh Parliament). After the institution was renamed from 'National Assembly for Wales' to 'Senedd Cymru' in 2020, the term MS (Member of the Senedd) has increasingly replaced AM, though both are still used. The Welsh Assembly was established in 1999 as part of the UK's devolution of powers.
常見錯誤
a.m. — abbreviation
1. a standard short code used on official paperwork, customs forms, and shipping la
a standard short code used on official paperwork, customs forms, and shipping labels to indicate that a person, item, or organisation is from the United States
The passenger wrote "AM" in the country-of-origin box on the customs form before landing in London.
written abbreviation on forms for nationality/origin
The embassy officer pointed to the "AM" code on the nationality line of the passport application.
The library catalogue used "AM" as the country code for every publisher based in the United States.
The visa application form listed "AM" as a citizenship code for United States nationals.
文法句型
a.m. + noun
written abbreviation on forms
2. a postal marking written on letters and packages to show they should be delivere
a postal marking written on letters and packages to show they should be delivered by aeroplane instead of by ship or truck — used on envelopes, labels, and customs forms
Before posting the birthday gift to her cousin in Tokyo, Mei-Lin wrote "AM" on the envelope for air delivery.
written on envelopes to indicate air delivery
The post office clerk stamped "AM" in bold red ink on the package bound for Hong Kong.
Letters marked "AM" cost NT$45 more than sea mail but arrive in three days instead of six weeks.
The shipping clerk ticked the "AM" box on the customs form to request air freight to London.
- air mail
the full two-word form of this abbreviation
- surface mail
mail sent by land or sea rather than by air
文法句型
marked + a.m.
stamped + a.m.
3. a written abbreviation for two different roles: 'Air Marshal' (capitalised, a se
a written abbreviation for two different roles: 'Air Marshal' (capitalised, a senior rank in the air force, used before a surname in British and Commonwealth military contexts) or 'air marshal' (uncapitalised, a federal security officer who works undercover on passenger aircraft to prevent hijacking).
Air Marshal Chen inspected the new fleet of fighter jets at the Royal Air Force base.
Air Marshal + surname — full title form for the military rank
The airport security report was signed by the air marshal who had monitored the overnight flights.
A former air marshal now teaches safety procedures to new recruits at the aviation training centre.
The captain quietly told the crew that an air marshal was in seat 14B on the flight to Dubai.
文法句型
a.m. + [surname]
used as a title before a name
用法筆記
In British and Commonwealth English, AM before a surname refers to a senior air force officer (Air Marshal). In American English, AM can refer to a federal air marshal who provides security on flights. The capitalisation and context (military vs. aviation security) distinguish the two.
4. a written abbreviation for a United States military award given to pilots, navig
a written abbreviation for a United States military award given to pilots, navigators, and flight crew for completing aerial missions with exceptional skill, courage, or achievement
The pilot's uniform displayed the AM ribbon alongside his other military decorations.
the + a.m. — used with definite article for the medal
The official citation for the AM described how the pilot rescued four crew members from a burning aircraft.
Her grandfather received the AM in 1968 for his service as a helicopter pilot in Vietnam.
The museum display case held an Air Medal from 1945 with a faded ribbon and a brass pin.
文法句型
the + a.m.
awarded + the a.m.
receive + the a.m.
5. a Latin abbreviation (anno mundi) used in historical and religious writing to co
a Latin abbreviation (anno mundi) used in historical and religious writing to count years from the assumed creation of the world according to biblical tradition.
The old manuscript placed the event at AM 2450 according to its timeline.
a.m. + year number — abbreviation before the numeral
The scholar's footnote read "AM 4004" next to the biblical creation date.
In the church records, the flood was dated to AM 1656 in the margin.
The history lecture compared dates from AM 1 to the modern calendar system.
文法句型
a.m. + [year number]
dated + a.m.
用法筆記
This abbreviation is placed before the year number (e.g. AM 3761), unlike the time abbreviation a.m. which comes after the number (e.g. 9 a.m.). This sense appears mainly in biblical scholarship, religious history, and Jewish calendar studies.
常見錯誤
6. an academic abbreviation placed after someone's name to show they have earned a
an academic abbreviation placed after someone's name to show they have earned a university graduate degree (Master of Arts) in a subject such as history, literature, philosophy, or languages — distinct from other post-nominal 'AM' uses like associate member of an organisation
The visiting lecturer was introduced as Diana Okafor, AM.
name + a.m. — placed after the name as a post-nominal
The university awarded her an AM in Economics after two years of study.
His business card read "James Chen, AM" just below his name.
The faculty directory listed Professor Olumide with an AM from Oxford.
- M.A.
the more common abbreviation in the United States for the same degree
文法句型
[name] + a.m.
a.m. after a person's name
用法筆記
The abbreviation AM is more common in British and Commonwealth universities. In the US, the equivalent degree is usually abbreviated as M.A. or MA.
7. a written abbreviation used after a person's name on membership lists, directori
a written abbreviation used after a person's name on membership lists, directories, and name badges to show they belong to a professional body or institution at a level with limited rights — typically without voting privileges or access to all benefits
The conference badge read "Fatima Al-Rashid, AM" to show her membership level.
name + a.m. — post-nominal membership level
The institute's newsletter listed new AMs who had joined that quarter.
As an AM, she could attend meetings but not vote on committee decisions.
The club divided its members into AM and full member categories.
- full member
a person with complete membership privileges in the same organization
文法句型
[name] + a.m.
a.m. after an organization title
8. a written abbreviation for 'Ave Maria', a traditional Catholic prayer addressed
a written abbreviation for 'Ave Maria', a traditional Catholic prayer addressed to the Virgin Mary, often found in hymnals, prayer books, and church programs
The program listed the A.M. as the final hymn of the evening service.
abbreviation used in written programs and schedules
Father Okafor pointed to the notation 'A.M.' in the missal and asked the choir to begin.
The medieval manuscript contained several musical settings of the A.M. with Latin notation.
During the wedding Mass, the congregation joined the choir in singing the A.M. after the final blessing.
文法句型
the + a.m.
sing + the a.m.
用法筆記
This abbreviation appears mainly in printed religious texts and church bulletins. In spoken language, the full phrase 'Ave Maria' or 'Hail Mary' is used instead.
9. a written abbreviation (using periods, as 'A.M.') for americium, a man-made radi
a written abbreviation (using periods, as 'A.M.') for americium, a man-made radioactive metallic element used in household smoke detectors and industrial gauges — distinct from the standard scientific symbol 'Am' which is written without periods
The periodic table entry for A.M. shows americium between plutonium and curium.
abbreviation used in periodic table contexts
A small sample of A.M. was shipped from the reactor to the laboratory for neutron testing.
The safety manual warned that A.M. must be stored inside a sealed lead container because it emits radiation.
Researchers at the nuclear laboratory studied how A.M. reacts when exposed to temperatures above 500 degrees.
Most household smoke detectors contain a tiny amount of americium-241, labelled A.M., in a sealed metal chamber.
文法句型
the + a.m.
a.m. + [noun]
用法筆記
The standard chemical symbol is 'Am' (without periods), but 'A.M.' appears occasionally in older or less formal written references to the element.
常見錯誤
a.m. — symbol
1. the official scientific symbol 'Am' (one capital letter followed by one lowercas
the official scientific symbol 'Am' (one capital letter followed by one lowercase letter, no periods) used on the periodic table and in chemical equations to represent the element americium — this is a scientific symbol, not an abbreviation, and differs from 'A.M.' (with periods) which may appear in general written references to the element
On the periodic table in the chemistry lab, Am sits between plutonium and curium near the bottom of the actinide row.
periodic-table context; symbol appears without periods
The chemistry teacher wrote the symbol 'Am' on the whiteboard and explained its place among the transuranium elements.
symbol used in an educational setting
Most smoke detectors contain americium-241, written as ²⁴¹Am in scientific notation on the label.
A lab manual warned that handling pure Am requires thick rubber gloves and a sealed fume hood for safety.
Thiago checked the periodic table poster on the classroom wall and found Am listed with an atomic mass of 243.
- Am
the standard form of the symbol as it appears in scientific writing; no periods or spacing
用法筆記
Unlike the abbreviation 'A.M.' (with periods), the chemical symbol 'Am' is written without periods and follows standard periodic-table capitalization rules: one capital letter, or one capital followed by one lowercase letter.