One

ainoa

(sole, only)

eräs

(a single, unspecified thing)

eräs

(being an unknown person with the specified name)

eräänä

(of a period of time)

kunnon

(being a preeminent example)

yhtä mieltä

(in agreement)

yksi

(a single, unspecified thing)

yksi

(whole, entire)

yksi

(the same)

dollarin seteli

(dollar bill)

ykkönen

(neutral element in multiplication)

ykkönen

(digit or figure)

yksi

(neutral element in multiplication)

yksi

(cardinal number 1)

does not exist

(indefinite personal pronoun; any person, people in general)