adjective

in vitro

in VEE-troh

In vitro (adjective) means taking place in a test tube, dish or other laboratory container rather than inside a living body. Example: “The compound killed the bacteria in vitro but failed in animal trials.”

adjective

technical Taking place in a test tube, dish or other laboratory container rather than inside a living body.

"The compound killed the bacteria in vitro but failed in animal trials."

"All in vitro results need confirming in a living system."

Of fertilisation: carried out in a laboratory, where an egg is combined with sperm outside the body and the resulting embryo is transferred to the womb. Usually in the phrase in vitro fertilisation (IVF).

"They conceived through in vitro fertilisation after four years of trying."

"The clinic offers three rounds of in vitro treatment."

How to Use In vitro

Learner’s notes

In plain EnglishDone in a lab dish rather than inside a living body.

When to use it

Technical and medical; borrowed from Latin, and often set in italics in academic writing.

Memory tip

Remember vitro by its link to vitreous and vitrine, both about glass.

Trace the full origin ↓

Easily confused with

in vivo in situ ex vivo

Common pairings

in vitro fertilisation in vitro study in vitro model

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Can you complete this real example?

The compound killed the bacteria _____ but failed in animal trials.

Etymology

From Latin in vitro, literally "in glass", a reference to the glass vessels used in laboratory work.

Origin: Latin

Antonyms

in vivo

Rhymes for in vitro

nitro

See all rhymes for in vitro →

Frequently Asked Questions

What is the difference between in vitro and in vivo?

In vitro means outside a living organism, in glassware or a culture dish; in vivo means inside a living organism, such as in a mouse or a human patient. A drug can work in vitro and still fail in vivo because a living body absorbs and breaks it down differently.

Is in vitro the same as IVF?

Not quite. IVF stands for in vitro fertilisation, which is one specific application. In vitro on its own is a general scientific term covering any experiment done outside the body.

How do you pronounce in vitro?

The most common English pronunciation is in VEE-troh, though in VIT-roh is also heard, particularly in the United States. Both are accepted.