Prefix · reversal / removal
Reverses or removes an action or condition: defrost, decode, deactivate, debug, dehydrate.
Written by Bryan López, English teacher · Updated
De- signals that an action is undone or reversed: frost → defrost (remove the frost), code → decode (reverse the coding), activate → deactivate (reverse the activation). It is the closest English equivalent to the Spanish prefix des- in its sense of reversal.
Beyond reversal, de- can signal removal or reduction: deforest (remove the forests), dehydrate (remove the water), devalue (reduce the value), delete (remove). In these cases there is not necessarily a prior action being undone; something is simply removed or reduced.
Attaches to verbs, nouns, and adjectives with no spelling change:
Pronunciation: /diː/ in everyday words (defrost, debug) and /dɪ/ in more formal words (devalue, dehydrate). Both are correct.
de-/diː/ or /dɪ/
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"Deactivate" reverses a previous activation; "disable" removes the ability to function. The difference is subtle but real in careful usage.
De- in "debug" signals removal. It is a technical programming term meaning to find and fix errors in code.
A trick to remember it
Think of de- as the English mirror of Spanish des-: defrost = descongelar, deactivate = desactivar, dehydrate = deshidratar. If you know the root, add de- to express the reverse action or the removal of something.
Exercise 1 · Form the word
Exercise 2 · Pick the right one
"Make sure to ___ the chicken in the fridge the night before you plan to cook it."
Exercise 3 · Pick the right one
What is the main difference between "de-" and "dis-"?
The prefix de- reverses or removes an action or condition: defrost, decode, deactivate, debug, dehydrate. In Spanish it usually maps to de- / des-.
The prefix de- is pronounced /diː/ or /dɪ/. For example, "defrost".
"frost" becomes "defrost". It is a typical example of the de- prefix.
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