one person; being alone; being by oneself; being single; being unmarried; by oneself
one day; all day (long); throughout the day; first day of the month
one thin flat object; one sheet
number one; first; best; most; game; round
first; foremost; most important; best; greatest; above all
once; one time; temporarily; for a moment; one degree; one tone
first place; first rank; unit's position; Japanese yew (Taxus cuspidata)
one tenth; one hundredth; one percent; one tenth of a sun; one quarter ryō (an old coin)
100,000,000; one hundred million
one class; one set; a pair; a suite; a series
from the beginning; from scratch
one Nth part (e.g. one fifth, one tenth); one out of N
(not even) an inch; (not even) a little bit; (lit.) one millimeter
one army; whole army; first string players; the cool kids; the popular kids
first year of high school; first-year high school student
(at a rate of) once a month; 10 percent monthly interest
first year of junior high school; first-year junior high school student
one face; one surface; the whole surface; one aspect; one side; (on) the other hand; one broad, flat object
first base; first baseman; one fort
first period (e.g. first class in school day)
one tablet; one pill; tray; salver
first person (to do); person going first; first place; top position; person in the top position
first year of elementary school; first year elementary school student
page in the history books; historical (event); old news
type 1 diabetes; juvenile diabetes
failing college entrance exams and retaking them a year later
one-part; single-part; single-component
Unit 731 (biological warfare unit of the Japanese Imperial Army)
primary cache; level 1 cache
September 11 attacks; 9/11
primary coil; primary winding (in transformer)