number-one
UK[ˈnʌmbə wʌn]US[ˈnʌmbər wʌn]
adj
most important, best, or most successful
n
the most important person or thing; the person or thing that is first in a list or series
Morpheme Breakdown
number
one
number
one
Etymology
The compound "number-one" is a straightforward combination of two fundamental English words of ancient lineage. "Number" traces back to the Latin numerus, meaning a count or quantity, while "one" originates from the Old English ān, itself from the Proto-Germanic ainaz, signifying a single unit. The logic of the phrase is purely ordinal, directly indicating the first position in a numerical sequence. Over time, this literal sense of being "first in order" evolved metaphorically to signify preeminence, superiority, or highest priority in non-numerical contexts, such as in ranking importance or success.
Analysis
Structure: number + one
- number: From Latin numerus (a number, quantity), via Old French nombre. Functions as a noun in this compound.
- one: From Old English ān (one), from Proto-Germanic ainaz. Functions as a numeral in this compound.
Examples
He is the number-one ranked tennis player in the world.
Customer safety is our number-one priority.
This issue is number one on the agenda for today's meeting.