English words ending in the spelling -mb occasionally give English learners difficulty. The error arises in trying to pronounce the final b.
Some of these words derive from originals that included the b sound and spelling.
Some, however, had the unnecessary, (sometimes called the “parasitic”), -b added after the words were in common use.
Here are some -mb words that come from roots that included the b as part of the spelling.
bomb [bŏm]- noun meaning an explosive device. From Italian bomba, possibly from Latin bombus, “a buzzing or booming sound” and Greek bombos “deep and hollow sound.”
climb [klīm] – verb meaning “to ascend.” He climbed the stairs. He climbed the cliff face. As a noun it means “an ascent.” It was an arduous climb. Climb is from the Old English verb climban.
comb [kōm] – noun (OE camb) meaning “a toothed implement.” As a verb it means to perform the act of running a comb through hair. It is also used figuratively to mean “examine with care.” She combed (or combed through) the files, looking for evidence.
dumb [dŭm] – (OE thumb; ON dumbr) meaning “mute.” The modern sense of “stupid” was influenced by German dumm, “stupid.”
jamb [jăm] – (Old French jambe, “side post of a door”) Ultimately from words meaning “leg,” a jamb is an upright piece of wood or other material that forms the side of a door, window, or other opening.
lamb [lăm] – This word for a baby sheep retains its OE spelling.
plumb [(plŭm)] The noun refers to a heavy object (usually a lead weight) tied to a string, used by builders to establish a vertical line. Plumb comes into English by way of Old French from the Latin word for lead [lĕd]:plumbum. (In case you ever wondered about the abbreviation for lead on the Periodic Table, now you know.) As a verb plumb can mean to make a wall straight, or determine the depth of something. It is used figuratively in the sense of examining something closely. Ex. He plumbed the depths of his soul.
tomb [tūm or toom] – a noun meaning a place of burial. The verb is “to entomb.” It came into English from French. At first the b was pronounced, but fell silent at some time in the 14th century.
womb [wūm or woom] – the uterus. From OE wamb or womb meaning “belly” or “uterus.”
The following words had the -b added to them after they had been in use without it.
crumb [krŭm] a small piece of something; from OE cruma. The verb crumble derives from OE gecrymman “to break into crumbs.” The -b may have got into the act by analogy with the French word humble.
limb [lĭm] – OE lim could mean the branch of a tree or a body member. The final -b began to appear on the word in the late 1500s.
numb [nŭm] – The adjective numb, meaning “devoid of feeling,” comes from the OE verb niman, “to take.” In 1440 the word existed as nome, “taken, seized.” A person who had been “taken” with shock or cold couldn’t feel normally. The unnecessary -b attached itself to the word during the 17th century, giving us numb.
thumb [thŭm] This word for the short fat digit that enables us to pick up things comes from OE thuma. The -b got attached to the word about 1290.