pyrethrum

noun
py·re·thrum | \ pī-ˈrē-thrəm , -ˈre- \

Definition of pyrethrum 

1 : any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides

2 : an insecticide made from the dried heads of any of several Old World chrysanthemums (especially Chrysanthemum cinerariaefolium)

Examples of pyrethrum in a Sentence

Recent Examples on the Web

Nymphs can be controlled with insecticidal soap, pyrethrum, rotenone or neem. Ellen Nibali, baltimoresun.com, "Garden Q&A: Black-eyed Susans with fungal leaf spot disease," 11 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'pyrethrum.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of pyrethrum

circa 1543, in the meaning defined at sense 1

History and Etymology for pyrethrum

Latin, pellitory, from Greek pyrethron, from pyr fire

Keep scrolling for more

Learn More about pyrethrum

Statistics for pyrethrum

Look-up Popularity

Time Traveler for pyrethrum

The first known use of pyrethrum was circa 1543

See more words from the same year

Keep scrolling for more

More Definitions for pyrethrum

pyrethrum

noun
py·re·thrum | \ pī-ˈrē-thrəm , -ˈreth-rəm \

Medical Definition of pyrethrum 

1 : any of several chrysanthemums with finely divided often aromatic leaves including ornamentals as well as important sources of insecticides

2 : an insecticide consisting of or derived from the dried heads of any of several Old World chrysanthemums (genus Chrysanthemum of the family Compositae)

More from Merriam-Webster on pyrethrum

Britannica.com: Encyclopedia article about pyrethrum

Comments on pyrethrum

What made you want to look up pyrethrum? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a magnificent or impressive array

Get Word of the Day daily email!

Test Your Vocabulary

Name that Food Quiz

Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!