theorize

verb

the·​o·​rize ˈthē-ə-ˌrīz 

ˈthir-ˌīz

theorized; theorizing

intransitive verb

: to form a theory : speculate

transitive verb

1

: to form a theory about

2

: to propose as a theory

theorization

ˌthē-ə-rə-ˈzā-shən 

ˌthir-ə-

noun

theorizer noun

Examples of theorize in a Sentence

Many scientists have theorized about the possibility of life on other planets.

Recent Examples on the Web

While climate change has had a negative effect on innumerable populations, Kohl theorizes that black vultures — and vultures, in general — may represent an exception. — Andrew Carter, Chicago Tribune, 19 July 2026

Historians theorize that, among several other factors, these sea peoples plundering the Mediterranean helped usher in a Dark Age where the ability to read and write was lost in Ancient Greece. — Eliana Dockterman, Time, 17 July 2026

Cherubim had theorized that some small, rocky planets like LHS 1140 b could develop atmospheres with large amounts of helium over time. — Adam Kovac, Scientific American, 16 July 2026

The discovery of Beta Pictoris d helps clear up a puzzle regarding a disk of dust and debris in this planetary system, which is theorized to be made of the leftovers of planet formation. — Robert Lea, Space.com, 15 July 2026

Word History

First Known Use

1644, in the meaning defined at transitive sense 1

Rhymes for theorize

• advise
• applies
• apprise
• arise
• assize
• baptize
• belies
• bitwise
• capsize
• chastise
• chordwise
• clockwise

Kids Definition

theorize

verb

the·​o·​rize ˈthē-ə-ˌrīz 

theorized; theorizing

: to form a theory : speculate

theorizer noun