one term, first term

one's lifetime

the first day of the month (solar or lunar calendar)

(obsolete) one day, 24 hours / (obsolete) the daytime, the period from dawn until dusk

(rare, obsolete) (all senses appear to be identical as for hitohi above)

(literary) one day, 24 hours / (literary) the daytime, the period from dawn until dusk / (literary) (figuratively) a short period of time

one week

one (of anything) / a, an

one (of anything) / a, an

(literary) an alternate name