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 of germ

• 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

This bar delivered thanks to its rich lather and moisturizing texture, a result of the lauric acid (which is a fatty acid that helps fight germs and emulsify the hard bar into a big, fluffy lather) baked in the soap. —Olivia Rose Rushing, InStyle, 7 Jan. 2026

Since they’re touched by everyone in the house all day and night long, these small surfaces accumulate a massive amount of germs and rarely get cleaned. —Elizabeth Brownfield, Southern Living, 7 Jan. 2026

Key Takeaways Vitamin C can boost your immune system by stimulating white blood cells, enabling them to fight germs more effectively. —Sarah Bence, Verywell Health, 5 Jan. 2026

Plaque is the sticky film of germs that can cause cavities and make your breath smell bad. —Linda Bartoshuk, The Conversation, 5 Jan. 2026

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