| Term | Entry | Related |
| m. | m. | - |
| Mace | Mace | - |
| Mackerel | Mackerel | - |
| Macles | Macles | See Mascle |
| Maconne | Maconne | - |
| Maconné | Masoned | - |
| Madder | Bag of Madder | - |
| Magpie | Magpie | - |
| Mahogany | Mahogany | - |
| Maiden's-head | Maiden's-head | - |
| Mail | Mail | - |
| Mailed | Mailed | - |
| Main | Main | - |
| Maintenance, Cap of | Maintenance, Cap of | - |
| Majesty, In His | Majesty, In His | - |
| Male-Griffin | Male-Griffin | - |
| Male-tiger | Male-tiger | See Heraldic Tiger |
| Mallard | Mallard | - |
| Malta, The Knight of | Malta, The Knight of | See Hospitallers |
| Maltale | Maltale | - |
| Man | Man | See Arm, Hand, Head, and Legs |
| Manche | Emanche | - |
| Manche | Manche | - |
| Mancher | Manchet | See Wastel-cake |
| Mancheron | Mancheron | - |
| Manchet | Manchet | See Wastel-cake |
| Mandrake | Mandrake | - |
| Maned | Maned | - |
| Mangonel | Mangonel | See Swepe |
| Man's Head | Man's Head | See Man's Head |
| Man's Head | Man's Head | - |
| Man's head on a dish | Man's head on a dish | - |
| Mantelée | Mantelle | See Chappe |
| Mantelle | Mantelle | See Chappe |
| Mantle | Mantle | See Robe |
| Mantlet | Mantlet | - |
| Mantling | Mantling | - |
| Mantling | Mantling | - |
| Mantyll | Mantyll | See Mantle |
| Man-wolf | Man-wolf | See War-Wolf |
| Map | Map | - |
| Marcassin | Marcassin | - |
| Marchioness | Marchioness | - |
| Marguette | Decked | - |
| Marigold | Marigold | See Marygold |
| Marined | Marined | - |
| Marine-wolf | Marine-wolf | - |
| Marks of Cadency | Distinction of Houses | See Cadency |
| Marks of Cadency | Marks of Cadency | See Cadency and Distinction of Houses |
| Marlet | Marlet | See Martlet |
| Marlions | Marlions | - |
| Marquess | Marquess | - |
| Marquis | Marquess | - |
| Mars | Mars | - |
| Mars | Mars | - |
| Marshal of England | Marshal of England | See Earl Marshal |
| Marshalling | Marshalling | See Pedigree |
| Marshal's Staff | Marshal's Staff | See Baton |
| Martel | Martel | - |
| Marten | Martin | - |
| Martin | Martin | - |
| Martin-cat | Martin | - |
| Martinet | Martlet | - |
| Martlet | Martlet | - |
| Marygold | Marygold | - |
| Mascally | Mascules | See Masculy, Masculy, covered with Mascles |
| Mascle | Mascle | - |
| Mascle-head | Mascle-head | - |
| Mascles conjoined | Mascles conjoined | - |
| Mascle-top | Mascle-head | - |
| Mascules | Mascules | See Masculy, Masculy, covered with Mascles |
| Mashes | Macles | See Mascle |
| Masoned | Masoned | - |
| Masonry | Masoned | - |
| Mastiff | Mastiff | - |
| Match | Match | - |
| Mateley | Aygnisee | See Urdée; Champain |
| Mateley-cross | Mateley-cross | - |
| Maul | Maul | - |
| Maunch | Emanche | - |
| Maunch | Manche | - |
| Maunche | Emanche | - |
| Maunche | Maunche | See Manche |
| Maunchenale | Maunche | See Manche |
| Maunchmale | Maunche | See Manche |
| Maw | Maw | - |
| Mawritanians Head | Mawritanians Head | - |
| Mayor | Mayor | - |
| md., mar. | m. | - |
| Mearemaid | Mearemaid | See Mermaid |
| Medal | Medal | - |
| Medieval | Medieval | - |
| Meire | Meire | - |
| Meirre | Meire | - |
| Melting Pot | Melting Pot | See Furnace |
| Melusina | Melusina | - |
| Membered | Legged | See Bird |
| Membered | Membered | - |
| Membre | Membre | - |
| Membrez | Membre | - |
| Meniver | Meniver | See Miniver |
| Menu of Vair | Menu of Vair | - |
| Menuvair | Menu of Vair | - |
| Merchant Service, Ensign of | Merchant Service, Ensign of | - |
| Merchant-Brig | Merchant-Brig | See Ship |
| Merchants' Marks | Merchants' Marks | - |
| Mercurial cap | Mercurys-cap | - |
| Mercury | Mercury | - |
| Mercury's Mace | Caduceus | - |
| Mercury's Soporiferous Rod | Caduceus | - |
| Mercurys-cap | Mercurys-cap | - |
| Merhon | Merlet | - |
| Merhon | Merhon | See Merlet |
| Meridian | Meridian | See Globe |
| Merillion | Merillion | - |
| Merle | Merle | - |
| Merlet | Merlet | - |
| Merlette | Merlet | - |
| Merlette-displayed | Merlette-displayed | - |
| Merlin | Merlin | See Falcon |
| Merlion | Martlet | - |
| Merlions-wings | Marlions | - |
| Merlotte | Merlotte | - |
| Mermaid | Mermaid | - |
| Merman | Merman | - |
| Mertlet | Mertlet | See Martlet |
| Mertrixes | Mertrixes | - |
| Mesle | Mesle | - |
| Mesles | Mesles | - |
| Metals | Metals | See Tinctures |
| Metamorphosed | Metamorphosed | - |
| Mew | Mew | - |
| Mew | Mew | - |
| Mewed-Hawk | Mewed-Hawk | - |
| Michael, St., and St. George | Michael, St., and St. George | See Knighthood |
| Mi-Couppe | Mi-Couppe | - |
| Midas-Head | Midas-Head | - |
| Middle Base Point | Middle Base Point | See Points of the Escutcheon |
| Middle chief point | Middle Base Point | See Points of the Escutcheon |
| Mill-Bill | Mill-Bill | See Mill Pick |
| Mill-ink | Fer de Moline | - |
| Mill-Ink | Mill-Rind | - |
| Mill-Inke | Mill-Inke | See Fer-de-Moline |
| Mill-Pick | Mill-Pick | - |
| Millrind | Fer de Moline | - |
| Mill-Rind | Mill-Rind | - |
| Mill-Rine | Mill-Rind | - |
| Mill-Stone | Mill-Stone | - |
| Minervas Head | Minervas Head | - |
| Miniver | Miniver | - |
| Minnow | Minnow | - |
| Minster | Minster | See Church |
| Mipartee | Mipartee | See Mi-Taille |
| Mi-Party | Mipartee | See Mi-Taille |
| Mirror | Mirror | - |
| Mi-Taille | Mi-Taille | - |
| Mitre | Mitre | - |
| Mitry | Mitry | - |
| Mitus | Mitus | - |
| Modilion | Modilion | - |
| Moile | Moile | - |
| Molet | Molet | See Mullet |
| Mollet | Molet | See Mullet |
| Monastery in ruins | Monastery in ruins | - |
| Moncheé | Maunche | See Manche |
| Monchee | Monchee | See Manche |
| Monk | Monk | See Hermit |
| Monkey | Ape | - |
| Monkey | Monkey | See Ape |
| Monogram | Monogram | - |
| Montant | Montant | - |
| Montese | Montese | - |
| Montese Cross | Mountain Cross | - |
| Monuments and Tombs | Monuments and Tombs | See Crest |
| Moon | Moon | See Crescent |
| Moor | Moor | - |
| Mooted | Mooted | - |
| Morfex | Morfex | - |
| Morion | Morion | - |
| Moriscos's Head | Moriscos's Head | - |
| Morne | Morne | - |
| Morse | Morse | - |
| Morse | Morse | - |
| Mortar | Mortar | - |
| Mortcours | Mortcours | - |
| Morteres | Mortcours | - |
| Morteries-Royalls | Mortcours | - |
| Morterres | Mortcours | - |
| Morthead | Morthead | See Mort's-head |
| Mortier | Mortier | - |
| Mortised | Mortised | See Enclave |
| Mortne | Morne | - |
| Mortne | Mortne | See Morne |
| Mort's-Head | Mort's-Head | - |
| Moses-Head | Moses-Head | - |
| Mossu | Mossu | - |
| Mossu | Mousue | - |
| mot. | Motto | - |
| Motto | Motto | - |
| Moulin | Moulin | See Fer-de-Moline |
| Moulted | Mooted | - |
| Moulted | Moulted | See Eradicated |
| Mound, from Mundus the world | Mound, from Mundus the world | - |
| Mount | Mount | - |
| Mountain Cross | Mountain Cross | - |
| Mountain-Cat | Mountain-Cat | See Cat-a-Mountain |
| Mountain-cross | Montese | - |
| Mountain-Inflamed | Mountain-Inflamed | - |
| Mounted | Mounted | - |
| Mount-Grieced | Mount-Grieced | - |
| Mount-Grieced | Mount-Grieced | - |
| Mounting | Mounting | - |
| Mourn | Mourn | - |
| Mourned | Mourn | - |
| Mouse-Rere | Mouse-Rere | See Reremouse |
| Moussue | Mossu | - |
| Mousue | Mousue | - |
| Mowrned | Mowrned | See Mousue |
| Moyle | Mule | - |
| Mule | Mule | - |
| Mullet | Mullet | - |
| Mullet | Mullet | - |
| Muraille | Muraille | - |
| Mural Crown | Mural Crown | See Crown |
| Murallée | Muraille | - |
| Murallee | Walled | - |
| Murex-Ferreus | Murex-Ferreus | See Galtrap |
| Murr | Murr | See Auk |
| Murrey-Colour | Murrey-Colour | - |
| Muschetors | Muschetors | - |
| Musimon | Musimon | - |
| Musion | Musion | See Cat-a-mountain |
| Musket | Musket | - |
| Muzzled | Muzzled | - |
| Myrtle Garland | Myrtle Garland | - |
| Mystic Pentagon | Pentagon | - |
