conversion

UK: /kənˈvɜː^rʃ^ən/

US: /kənˈvɝʒən, -ʃən/

US: (kən vûr′zhən, -shən)

WordReference Random House Learner's Dictionary of American English © 2026

con•ver•sion /kənˈvɜrʒən, -ʃən/   n. 

1. the act or process of converting or the state of being converted:
   [uncountable] chemical conversion.
2. change from one belief, etc., to another:
   [countable] a political conversion from one party to another.
   [uncountable] People doubt the sincerity of his conversion to supply-side economics.
3. a change of one kind of component for another:
   [uncountable] conversion from oil heat to gas heat.
4. Sport [countable] the making of an additional score in football or basketball.

See -vert-.

WordReference Random House Unabridged Dictionary of American English © 2026

con•ver•sion  (kən vûr′zhən, -shən), n. 

1. Philosophy the act or process of converting; state of being converted.
2. change in character, form, or function.
3. Religion spiritual change from sinfulness to righteousness.
4. change from one religion, political belief, viewpoint, etc., to another.
5. a change of attitude, emotion, or viewpoint from one of indifference, disbelief, or antagonism to one of acceptance, faith, or enthusiastic support, esp. such a change in a person's religion.
6. Physics a physical transformation from one material or state to another:
   conversion of coal, water, and air into nylon.
7. the act of obtaining equivalent value, as of money or units of measurement, in an exchange or calculation:
   conversion of francs into dollars.
8. a physical, structural, or design change or transformation from one state or condition to another, esp. to effect a change in function:
   conversion of a freighter into a passenger liner.
9. a substitution of one component for another so as to effect a change:
   conversion from oil heat to gas heat.
10. Mathematics a change in the form or units of an expression.
11. Philosophy [Logic.] the transposition of the subject and predicate of a proposition, as "No good man is unhappy'' becomes by conversion "No unhappy man is good.''
12. Law
    • unauthorized assumption and exercise of rights of ownership over personal property belonging to another.
    • change from realty into personalty, or vice versa, as in the sale or purchase of land or mining coal.
13. Sport [Football.] a score made on a try for a point after touchdown by place-kicking or drop-kicking the ball over the bar between the goalposts or by completing a pass in or running the ball into the end zone.
14. Psychiatry the process by which a repressed psychic event, idea, feeling, memory, or impulse is represented by a bodily change or symptom.
15. Physics the production of radioactive material in a process in which one nuclear fuel is converted into another by the capture of neutrons. Cf. breeding (def. 6).
16. Computing
    • the process of changing software designed to run on one computer system to run on another.
    • the change from an existing computer system to a new computer system.
    • the act of transferring or copying data stored on one storage medium to another storage medium.
    • the process of changing the base that a number or numbers are written in.
17. Printing the transformation of material from a form suitable for printing by one process to a form suitable for another process:
    a halftone gravure conversion.

• Latin conversiōn- (stem of conversiō) a complete change. See converse², -ion
• Anglo-French)
• Middle English conversio(u)n (1300–50

con•ver′sion•al, con•ver•sion•ar•y  (kən vûr′zhə ner′ē, -shə-), adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

conversion / kənˈvɜːʃən/ noun

1. a change or adaptation in form, character, or function
2. something changed in one of these respects
3. a change to another attitude or belief, as in a change of religion
4. a change in the units or form of a number or expression: the conversion of miles to kilometres involves multiplying by 1.61
5. a form of inference by which one proposition is obtained as the converse of another proposition
6. unauthorized dealing with or the assumption of rights of ownership to another's personal property
7. the changing of real property into personalty or personalty into realty
8. a score made after a try by kicking the ball over the crossbar from a place kick
9. a change of fertile material to fissile material in a reactor
10. an alteration to a car engine to improve its performance

Etymology: 14th Century: from Latin conversiō a turning around; see convert