Prefix · self / automatic
Signals self-action or automaticity: automatic, autobiography, autopilot, autograph.
Written by Bryan López, English teacher · Updated
Auto- comes from the Greek autos, which means "self" or "by itself". It shows that something happens on its own, without outside help, or that it refers to oneself. It is one of the easiest prefixes to spot, and one of the most useful.
Auto- is one of the most used prefixes in modern technology: every time a phone, an app or a machine does something by itself, the word very likely starts with auto-. It also appears in everyday words, like when something is done by the person themselves. If you learn this prefix, you understand the menus of almost any app in English.
Attaches to nouns and adjectives with no spelling change. Modern English usually writes it without a hyphen:
Pronunciation: /ˈɔːtəʊ/, with the "au" long as in "thought." In informal use, "auto" alone means "car" in some varieties of English and in several other languages.
auto-/ˈɔːtəʊ/
Tap the button to hear how the prefix sounds. Each word in the table has its own audio.
"Autobiography" = auto (self) + bio (life) + graphy (writing) = the person writes about their own life. "Biography" = someone else writes about the subject's life. The prefix auto- marks who the author is.
"Autonomous" = capable of making its own decisions (a self-driving car is autonomous). "Automatic" = operates by itself without requiring human action each time (an automatic door, an automatic gearbox). A car can be automatic (no manual gearshift) without being fully autonomous (without being able to drive itself).
A trick to remember it
Think of your car on autopilot: it drives itself. auto- = by itself. automatic, autobiography.
Exercise 1 · Form the word
Exercise 2 · Pick the right one
"The car has an ___ braking system that stops the vehicle before the driver can even react."
Exercise 3 · Pick the right one
What is the difference between "autobiography" and "biography"?
The prefix auto- signals self-action or automaticity: automatic, autobiography, autopilot, autograph.
The prefix auto- is pronounced /ˈɔːtəʊ/. For example, "automatic".
"matic" becomes "automatic". It is a typical example of the auto- prefix.
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