one

Dictionary definition · one

the smallest whole number or a numeral representing this number"he has the one but will need a two and three to go with it"
a single person or thing"he is the best one"

used of a single unit or thing; not two or more"‘ane’ is Scottish"
having the indivisible character of a unit"a unitary action"
of the same kind or quality"two animals of one species"
(informal) very; used informally as an intensifier"that is one fine dog"
indefinite in time or position"he will come one day"
being a single entity made by combining separate components"three chemicals combining into one solution"
eminent beyond or above comparison"matchless beauty"

Source: Open English WordNet (CC BY 4.0).