germ

noun

ˈjərm 

plural germs

1

a

: a small mass of living substance capable of developing into an organism or one of its parts

b

: the embryo with the scutellum of a cereal grain that is usually separated from the starchy endosperm during milling

2

: something that initiates development or serves as an origin : rudiments, beginning

3

: a microorganism causing disease : a pathogenic agent (such as a bacterium or virus)

broadly : microorganism

Synonyms

• origin
• root
• seed
• beginning

Examples of germ in a Sentence

the germ that causes tuberculosis

the germ of an idea

the germ layers of an embryo

Recent Examples on the Web

Linus Pauling: Fallout, radioactive fallout, causes damage to the pool of human germ plasm, in that will result–that does result–in the birth of an additional number of defective children. —Carol Sutton Lewis, Scientific American, 18 June 2025

Walking barefoot or in socks to the restroom is unhygienic and often regretted due to potential exposure to germs. —Christopher Elliott, USA Today, 17 June 2025

Post-exposure prophylaxis is offering someone a drug or vaccine after they are exposed to a germ, to reduce the chance they will be infected or develop severe disease. —Sarah Lynch Baldwin, CBS News, 17 June 2025

Antibodies mark and bind to foreign substances (such as germs) for destruction, whereas cytokines serve as messengers, informing and signaling the immune system to launch an attack against germs. —Jonathan Purtell, Verywell Health, 13 June 2025

Word History

Etymology

French germe, from Latin germin-, germen, from gignere to beget — more at kin

First Known Use

circa 1550, in the meaning defined at sense 2

Phrases Containing germ

• germ cell
• germ-free
• germ layer
• germ line
• germ plasm
• germ theory
• germ warfare
• wheat germ

Rhymes for germ

• berm
• ferm
• firm
• herm
• sperm
• squirm
• term
• therm
• worm
• wurm
• affirm
• bookworm

Kids Definition

germ

noun

ˈjərm 

1

a

: a small mass of living substance capable of developing into a whole individual or one of its parts

b

: the embryo in the seed of a cereal (as corn or wheat) together with its cotyledon that is usually separated from the starchy part of the seed during milling

2

: something that serves as an origin

the germ of an idea

3

: a microscopic living thing

especially : one that causes disease

Medical Definition

germ

noun

ˈjərm 

1

: a small mass of living substance capable of developing into an organism or one of its parts

2

: a microorganism causing disease : a pathogenic agent (as a bacterium or virus)

broadly : microorganism