verb pen·e·trate \ˈpe-nə-ˌtrāt\

Definition of penetrate




  1. transitive verb
  2. 1a :  to pass into or through this route … penetrates the leading resort and lake areas — American Guide Series: Minnesota Only a dirt road penetrates the rough, wooded terrain.b :  to enter by overcoming resistance :  pierce This bullet can penetrate armor.c :  to gain entrance to an apartment that I now penetrated for the first time — Osbert Lancaster

  3. 2a :  to see into or through their keen eyes can penetrate the water to a depth of … forty feet — L. K. Porrittb :  to discover the inner contents or meaning of a scientific secret which will eventually be penetrated by other countries — Vera M. Dean

  4. 3 :  to affect profoundly with feeling men may still be penetrated with awe by the divine righteousness — R. W. Dale

  5. 4 :  to diffuse through or into the cold began to penetrate his bones — E. K. Gann

  6. intransitive verb
  7. 1a :  to pass, extend, pierce, or diffuse into or through something fishes … which enter tidal rivers and penetrate almost to fresh water — J. L. B. Smithb :  to pierce something with the eye or mind strained his eyes to penetrate beyond the thick cloud of dust insight that penetrates to the very heart of some … problem — W. F. Hambly

  8. 2 :  to affect deeply the senses or feelings the suggestion might penetrate deeply enough … to make her a good deal more wary — H. A. Overstreet

Examples of penetrate in a sentence

  1. These bullets can penetrate armor.

  2. radiation penetrating the Earth's atmosphere

  3. The bullet failed to penetrate.

  4. The heat penetrated through the wall.

  5. The roots of these plants have been known to penetrate to a depth of more than 15 feet.

  6. My car's headlights couldn't penetrate the dense fog.

Origin and Etymology of penetrate

Latin penetratus, past participle of penetrare, from penitus deep within, far; akin to Latin penus provisions

First Known Use: circa 1530

Synonym Discussion of penetrate

enter, penetrate, pierce, probe mean to make way into something. enter is the most general of these and may imply either going in or forcing a way in entered the city in triumph. penetrate carries a strong implication of an impelling force or compelling power that achieves entrance the enemy penetrated the fortress. pierce means an entering or cutting through with a sharp pointed instrument pierced the boil with a lancet. probe implies penetration to investigate or explore something hidden from sight or knowledge probed the depths of the sea.

PENETRATE Defined for English Language Learners


verb pen·e·trate \ˈpe-nə-ˌtrāt\

Definition of penetrate for English Language Learners

  • : to go through or into something

  • : to see or show the way through (something)

  • : to succeed in becoming part of (an organization, a community, etc.)

PENETRATE Defined for Kids


verb pen·e·trate \ˈpe-nə-ˌtrāt\

Definition of penetrate for Students




  1. 1 :  to pass into or through A nail penetrated the tire. But his voice was not strong enough to penetrate the thick wall. — E. B. White, Stuart Little

  2. 2 :  to see into or through My eyes couldn't penetrate the darkness.

Medical Dictionary


verb pen·e·trate \ˈpen-ə-ˌtrāt\

Medical Definition of penetrate




  1. 1

  2. transitive verb

  3. :  to pass into or through enzymes that help the sperm penetrate the zona pellucida—Anna Maria Gillis

  4. 2:  to insert the penis into the vagina of in copulation

  5. intransitive verb

  6. :  to pass, extend, pierce, or diffuse into or through something penetrating percutaneous nephroscopy or ureteroscopy—R. A. Riehle et al

Seen and Heard

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


soon or gladly

Get Word of the Day daily email!


Take a 3-minute break and test your skills!

  • shamrock
  • What is the best definition of green-eyed monster?
Name That Thing

Test your visual vocabulary with our 10-question challenge!


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