first-year student; first-grade student, freshman / (botany) annual / beginner, inexperienced

master sergeant

one ship or boat

a piece of news; tidings; information

a male given name

Used other than figuratively or idiomatically: see 一, 発. / doing something only once / (baseball, informal) home run

A solar year, the time it takes the Earth to complete one revolution of the Sun (between 365.24 and 365.26 days depending on the point of reference)

(a duration of) one year / an unspecified year in the past

task; (doing a) bit of work / difficult task; hard work

(slang) the only choice, the one possible option