How Well Do You Know Your Pre-, Dis-, Un- and Re- Prefixes?

The prefix pre- means "before in time or order," as seen in words like predict (to say before) and prehistoric (before recorded history). Cambridge University Press highlights its consistent use to establish temporal relationships. A handy mnemonic is "PRior to Everything" to remember pre-.

Re- signifies repetition or return, appearing in words like rebuild (build again) and revert (turn back). According to Oxford English Dictionary guidelines, re- is unstressed when simply meaning "again," but stressed when implying "back" (reCORD vs REcord). Think "REpeat Everything" to lock in the idea of doing something anew.

Un- forms opposites for adjectives, adverbs, and verbs (e.g., unhappy, unlock), as detailed by Purdue OWL's morphology notes. It simply means "not" or "the opposite of," and is the most versatile negative prefix in English. Use the phrase "Un = Not One" to recall its broad "not" function.

Dis- conveys not, opposite of, or separation (e.g., disconnect, disapprove); it appears frequently in formal registers, as noted by Merriam-Webster's usage panel. Unlike un-, dis- sometimes implies an active undoing, such as disassemble (take apart). Remember "DISassemble = DISassemble," where the prefix literally "dissolves" the base word.

When combining multiple prefixes (prefixes pre dis un re), academic sources like the University of Manchester warn to respect morphological hierarchy - temporal pre- before negative un- or dis-, and core meaning-altering re- last. For example, pre- + assign + ment → preassignment, not re-un-assign. A helpful trick is "Time-Negative-Core-Repeat" to sequence Pre, Dis/Un, then Re.