- M ... M44
- M45 ... Maazel, Lorin Varencove
- Mab ... MacArthur Park
- MacArthur, Catherine ... MacDonald, Malcolm
- Macdonald, Margaret ... Machado y Morales, Gerardo
- Machado y Ruiz, Antonio ... Macías Nguema, Francisco
- Macina ... MacLane, Mary Elizabeth
- MacLaren, Archibald ... Macrae, Gordon
- macrame ... macular degeneration
- Maculinea arion ... Madanīn
- Madaniyyah ... Madhya Bharat National Park
- Madhya Bharat Pathar ... Madonna della Stella
- Madonna della Vittoria ... Mae Nam Khong
- Mae Nam Khwae Noi ... magainin
- Magalhães, Domingos José Gonçalves de ... magic
- Magic ... magnesioferrite
- Magnesiopolis ... magnetism
- magnetism, terrestrial ... Magnum Concilium
- Magnum Opus Musicum ... Maha Moggallana
- Maha Nuwara ... Mahasena
- mahasiddha ... Mahkamah Agung
- Mahkato ... Maidan protest movement
- Maidan Square ... Main Street
- Main, army of the ... Maistre, P.-A.-M.
- Maistre, Xavier de ... Major Dundee
- major figures in Greek mythology ... Make America Great Again movement
- Make and Break ... Makrani language
- Makri rug ... Malakal
- Malakbel ... Malayo-Polynesian languages
- Malaysia ... maleic hydrazide
- Malek, Rami ... Mālikī, Jawad al-
- Maliki, Nouri al- ... mallow
- mallow family ... Maltese
- Maltese ... Mama Said
- Mama Said Knock You Out ... Mamry
- Mamucium ... man orchid
- Man Ray ... Manacus
- Manado ... Manchester Museum
- Manchester school ... Mande languages
- Mandel, Georges ... maneuverability
- maneuvering warhead ... Mangrai
- mangrove ... Manila Bay
- Manila Bay, Battle of ... Manley, Michael Norman
- Manley, Norman ... Mano River
- Mano Valley ... Manṣūr
- Manṣūr ibn Yūnus al-Bahūtī, Shaykh ... Manu National Park
- Manu’a Islands ... many-coloured bush-shrike
- many-plumed moth ... maple
- Maple Leaf Flag ... maracuyá
- Maradi ... marbled cat
- marbled godwit ... March, earls of
- March, Edmund Mortimer, 5th Earl of ... Marcus Aurelius Claudius Quintillus
- Marcus Aurelius Numerius Numerianus ... Marengo, Battle of
- marennes ... Margin Call
- Margin for Error ... Maria Luise Augusta Katharina
- María Madre ... Marie-Magdeleine
- Marie-Strümpell arthritis ... marine oil
- Marine One ... Maritima
- maritime air mass ... Market Anti-Inflation Plan
- market conduct ... Marlborough: His Life and Times
- Marleau, Patrick ... Marozia
- Marpessa ... Married Man, The
- Married to Laughter: A Love Story Featuring Anne Meara ... marsh Labrador tea
- marsh mallow ... marsupial frog
- marsupial mole ... Martin I
- Martin I ... Martinelli, Drusiano
- Martinelli, Ricardo ... Martyrdom of Saint Matthew, The
- Martyrdom of Saint Maurice ... Mary Magdalene
- Mary Magdalene, St. ... Masamune
- Masamune Hakuchō ... Masisi, Mokgweetsi
- Masitala ... Mason, John Mitchell
- Mason, John Y. ... mass-communication city
- mass-energy ... Masson, André-Aimé-René
- Masson, Antoine ... Masterton, Bill
- mastic ... Matamoros
- Matamoros de Izúcar ... Matesis, Antonios
- Mateus da Graça, José Vieira ... Mathis, Johnny
- Mathis, June ... matrix
- matrix ... matter, conservation of
- matter, fallacy in ... matzahs
- matzas ... Maurepas, Jean-Frédéric Phélypeaux, comte de
- Maurer, Alfred Henry ... Mawaggali, Saint Noe
- mawālī ... maximite
- Maxims and Moral Reflections ... Mayagüez
- Mayaguez ... Maynila
- Maynilad ... Mazartag Mountains
- Mazaruni River ... Mbala
- mbalax ... McCall Smith, Sandy
- McCall’s ... McCormack, Win
- McCormick ... McDonald, Ronald
- McDonnell Aircraft Corporation ... McGuire, Alfred James
- McGuire, Barry ... McLaren, Jack
- McLaren, Malcolm ... McNeill, William H.
- McNeill, William Hardy ... Me-ʿam Loʿez
- mead ... Meany, George
- Meara, Anne ... mechanical picture
- mechanical powdering ... Meddows-Taylor, Roger
- Mede ... medical imaging
- Medical Inquiries and Observations upon the Diseases of the Mind ... Medieval Hebrew language
- medieval law ... Medium, The
- medium-bypass turbofan ... Meeting Gorbachev
- Meeting of Attila and Pope Leo ... Megasoma
- Megasoma actaeon ... Meḥmet ʿAlī Pasha
- Mehr al-Nesāʾ ... Meir, Aubrey Solomon
- Meir, Golda ... Melancholy Baby
- Melanchthon, Philipp ... Meleagrididae
- Meleagrina ... Mellors, Oliver
- Mellotron ... Melville, Henry Dundas, 1st Viscount
- Melville, Herman ... Memoirs of a Professional Cad
- Memoirs of a Secret Revolutionary ... Memphis Sound
- Memphis State College ... Mende
- Mendel’s first law ... Mēness
- menestral ... Menno Simonszoon
- Mennonite Central Committee ... Mentha × piperita
- Mentha aquatica ... mercapto group
- mercaptoacetic acid ... Mercurialis perennis
- mercuric chloride ... Meres, Francis
- Meretz ... Merleau-Ponty, Maurice
- MERLIN ... Merrimack and Monitor, Battle of
- Merrimack River ... Mes Hôpitaux
- Mes Prisons ... mesoclimate
- Mesocricetus auratus ... Messager, André
- Messager, André-Charles-Prosper ... Mesud
- Mesurethra ... Metallifere Mountains
- Metallo-Magic ... metastasis
- Metastigmata ... metestrus
- Metey midbar ... methyl ethyl ketone
- methyl group ... Metrophanes Kritopoulos
- Metropolis ... Mexican
- Mexican abelia ... Meydān-e Shāh
- Meyer, Adolf ... MG1
- MG2 ... Miastor
- MIBG ... Michel, Robert
- Michel, Robert Henry ... micro topography
- micro-tidal coast ... microfinance
- microfluidic system ... Microsoft Corporation
- Microsoft Disk-Operating System ... mid-oceanic rift
- Mid-Sahara Rise ... Middle Persian language
- Middle Plantation ... Midland
- Midland Bank PLC ... Miege disease
- Miehen tie ... Migration of the American Negro, The
- Migration period ... Mikroscopische Beschaffenheit der Mineralien und Gesteine
- Mikroskopische Physiographie der petrographische wichtigen Mineralien ... Milescu, Nicolae
- Milesia fabula ... military rule
- military science ... Mille, James De
- Milledgeville ... Miller, Max
- Miller, May ... Millroy the Magician
- Mills Brothers, the ... Milwaukee
- Milwaukee Art Museum ... mina
- Mina ... Mindanao Trench
- Mindanao, University of ... Ming Antu
- ming aralia ... minimally invasive surgery
- minimax principle ... Minnesota E-Democracy
- Minnesota Lynx ... Minshatō
- Minshu Shakaitō ... Mīr Qamar-ud-Dīn
- Mīr Qasīm ... Miranda, Ernesto
- Miranda, Francisco de ... Mirrour of Mirth and Pleasant Conceits, The
- Mirrour of the World ... Mishnayot
- Mishne Torah ... missense mutation
- missi comitis ... Mississippi School for the Deaf
- Mississippi Southern College ... MIT Media Laboratory
- MIT Radiation Laboratory ... Mithridates VI Eupator
- Mithridates VI Eupator Dionysus ... mitsvot
- mitsvoth ... Miyabe maple
- Miyagawa Chōshun ... MLR
- MLS ... moat
- Moawad, René ... Mochihito-ō
- Mochlos ... moderate intuitionism
- Moderate Party ... modernization
- Modersohn, Otto ... Moero, Lac
- Moers ... Mohammed I Askiya
- Moḥammed Raḥīm ... Mojave rattlesnake
- Mojave thorn ... mole
- mole ... Molitor, Paul Leo
- Moll Cutpurse ... MoMA Poll
- MoMA PS1 ... Monarch Butterfly Biosphere Reserve
- monarch flycatcher ... Monet, Claude
- Moneta, Ernesto Teodoro ... Monguor
- Monguor language ... Monmouth, Harry
- Monmouth, James Scott, duke of ... monolithic church
- monolithic filter ... Monroe Doctrine
- Monroe, Bill ... Mont
- Mont Beuvray ... Montauban, Guillaume de
- Montauk ... Monterrey Institute of Technology and Higher Education
- Monterrey, Battle of ... Monticelli, Adolphe-Joseph-Thomas
- monticellite ... monument
- Monument ... moon worship
- moon wrasse ... Moore, George
- Moore, George Edward ... Moraes, Dominic Francis
- Moraes, Vinícius de ... Moravian Brethren
- Moravian church ... Morella
- Morella ... Morgan, Joseph Leonard
- Morgan, Julia ... Morita Akio
- Morita Kan’ya XIV ... Morocco earthquake of 2023
- Morocco ironwood ... Morris, Errol
- Morris, Esther Hobart ... morse
- morse ... Morton, William Thomas Green
- Morts, Les ... Moscow on the Hudson
- Moscow Peak ... Moskva, Kanal
- Moskvin, Ivan ... Mosul school
- Moszkowski, Moritz ... Mothersbaugh, Mark
- Mothershed, Thelma ... motor sailer
- motor sports ... Moulin, Jean
- moulinet ... Mount Sinai
- Mount St. Mary’s University ... Mountain Zebra National Park
- Mountain, The ... mouth fungus
- mouth organ ... Movimiento 26 de Julio
- Movimiento al Socialismo ... Mozambique, Republic of
- Mozarab ... Mr. A’s Amazing Maze Plays
- Mr. A. Mutt ... Mrożek, Sławomir
- MRP ... Mtshali, Oswald Mbuyiseni
- Mtskheta ... mucus tract
- MUD ... Mufulira
- Mufumbiro Mountains ... Muḥammad ibn Wahb al-Qurashī
- Muḥammad ibn Zāyid ibn Sulṭān Āl Nahyān ... Muir Woods National Monument
- Muir, Edwin ... Mulcahy, Anne
- Mulcahy, Richard James ... Müller-Brockmann, Josef
- Müller-Lyer illusion ... multinomial coefficient
- multinomial distribution ... mulūk at-ṭawāʿif
- mulukhiyyah ... Munday, Jeremy
- Mündel will Vormund sein, Das ... Munkar
- Munkhafaḍ al-Qaṭṭārah ... Muqdisho
- Muqi ... Murder in the White House
- Murder Man ... Murmur of the Heart
- Murmuring Judges ... Murray, Joseph E.
- Murray, Joseph Edward ... Mûsa Bey
- Musa coccinea ... MUSE
- Muse ... Mushku
- mushrabiyyah ... musical film
- musical form ... Musnad
- Musō Soseki ... Mustela rixosa
- Mustela sibirica ... Mutual Aid: A Factor in Evolution
- Mutual and Balanced Force Reductions ... MVR
- MVT deposit ... My Gal Sal
- My Generation ... My Tho
- My Three Stooges ... myelocyte
- myeloencephalitis ... Myoprocta
- Myoprocta acouchy ... Myrtle Beach
- myrtle beech ... Mysuru
- Mysuru Palace ... Mʾzabite