Word Games
Word of the Day
New Words & Slang
Video
My Favorites
View your list of saved words.
(You can log in using Facebook.)

SIV

noun \ˌes-ˌī-ˈvē\

Definition of SIV

: a retrovirus of the genus Lentivirus (species Simian immunodeficiency virus) that causes a disease in monkeys similar to AIDS and that is closely related to HIV-2 of humans—called also simian immunodeficiency virus

Learn More About SIV

Dictionary: Definition of "SIV"

Test Your Vocabulary

Take Our 10-Question Quiz


	Name That Thing Take our visual vocab quiz Test Your Knowledge »

	True or False? A quick quiz about stuff worth knowing Take It Now »


	Join Us on FB & Twitter Get the Word of the Day and More Facebook \| Twitter

	Get Our Free Apps Voice Search, Favorites, Word of the Day, and More iPhone \| iPad \| Android \| More

SIV

SIV

Definition of SIV

Learn More About SIV

Test Your Vocabulary

The Merriam-Webster

Unabridged Dictionary

Learning English?

We can help.

Our Dictionary,
On Your Devices

Visit Our Store

Join Us

Bookstore: Digital and Print

Other Merriam-Webster Dictionaries

SIV

SIV

Definition of SIV

Learn More About SIV

Test Your Vocabulary

Name That Thing

True or False?

Join Us on FB & Twitter

Get Our Free Apps

The Merriam-Webster

Unabridged Dictionary

Learning English?

We can help.

Our Dictionary,On Your Devices

Visit Our Store

Join Us

Bookstore: Digital and Print

Other Merriam-Webster Dictionaries

Our Dictionary,
On Your Devices