What does odd mean?
Odd is a versatile adjective describing what is strange, unusual, mismatched, or outside the normal pattern. In informal contexts, it can describe a person as eccentric or behavior as suspicious, although the implication varies from playful teasing to disapproval. Its second major sense concerns numbers and quantities that cannot be divided evenly by two, making it a basic term in arithmetic. The word is also used for things that do not fit a regular arrangement, such as an odd job or the odd one out in a group. Because it combines a specific mathematical meaning with a broader suggestion of irregularity, “odd” is useful whenever something is not merely different in degree but genuinely outside an expected category.
Strange, unusual, or different from what is expected; eccentric or mismatched in informal contexts.
"There was something odd about his explanation."
The informal sense can be mildly disapproving or teasing, while the mathematical sense is neutral.
Not divisible by two, or consisting of a number that cannot be divided evenly by two.
"The lottery selected three odd numbers."
This is the standard mathematical sense.
An eccentric or strange person; also, an odd number.
"The old eccentric was known throughout the village as the local odd."
The noun sense meaning an eccentric person is informal and comparatively uncommon.
The plural is standard in expressions such as “the odds” and “against all the odds.” The singular noun meaning an eccentric person is rarely pluralized.
"Against all the odds, the team reached the final."
The odd numbers begin with one, while the even numbers begin with two: together, they form the foundation of counting.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does odd come from?
The word comes through Middle English from a Germanic source related to Old Norse “oddi,” meaning an odd number, and ultimately to a Proto-Germanic root associated with unevenness or irregularity. Its original sense referred to numbers that could not be divided into equal pairs. The broader meaning, meaning strange or unusual, developed by extension from the idea of irregularity or exception.
Related word forms
How odd is actually used
In its sense of strange or eccentric, “odd” is common in everyday speech and can sound mildly critical, amused, or disapproving depending on context. The mathematical sense is neutral and standard.
Easily confused with odd
“Odd” means a number that cannot be divided evenly by two, whereas “even” means one that can.