1once 
/ˈwʌns/ adverb
/ˈwʌns/ adverb 1 : one time only
▪ I will repeat the question once. ▪ We try to get together (at least) once every month. ▪ The play was performed only once. ▪ He had ridden a horse only once (before). ▪ We go to the movies once or twice a month. [=we go to the movies a few times a month] ▪ I've only seen her once or twice. [=I have only seen her a few times] 2 : at any one time : ever
▪ She didn't once thank me. ▪ He didn't look at me once. 3 : at some time in the past
▪ It was once done that way. ▪ A river once flowed through this canyon. ▪ It was once a booming mining town. ▪ Their music was once very popular. — sometimes used in combination ▪ a once-successful actor ▪ a once-popular restaurant
▪ I will repeat the question once. ▪ We try to get together (at least) once every month. ▪ The play was performed only once. ▪ He had ridden a horse only once (before). ▪ We go to the movies once or twice a month. [=we go to the movies a few times a month] ▪ I've only seen her once or twice. [=I have only seen her a few times]
▪ She didn't once thank me. ▪ He didn't look at me once.
▪ It was once done that way. ▪ A river once flowed through this canyon. ▪ It was once a booming mining town. ▪ Their music was once very popular. — sometimes used in combination ▪ a once-successful actor ▪ a once-popular restaurant
once again/more
: for another time : one more time : again
▪ Let me explain the problem once again. ▪ Once again, you've ignored my instructions. ▪ Could I hear the question once more?
▪ Let me explain the problem once again. ▪ Once again, you've ignored my instructions. ▪ Could I hear the question once more?
once and for all
: now and for the last time
▪ Let's settle this problem once and for all. ▪ Winning its fourth straight championship game, the team proved once and for all that they are the best. ▪ I'm asking you once and for all. ▪ Please, once and for all, stop worrying.
▪ Let's settle this problem once and for all. ▪ Winning its fourth straight championship game, the team proved once and for all that they are the best. ▪ I'm asking you once and for all. ▪ Please, once and for all, stop worrying.
once bitten, twice shy — see 1bite
once in a blue moon — see blue moon
once in a while
: sometimes but not often : occasionally
▪ We spend most of our time at home and go out once in a while. ▪ Every once in a while, we have wine with dinner.
▪ We spend most of our time at home and go out once in a while. ▪ Every once in a while, we have wine with dinner.
once upon a time
: at some time in the past
▪ He was a famous actor once upon a time. ◊Once upon a time is the traditional way to begin a fairy tale.
▪ Once upon a time, there was a beautiful princess named Snow White.
▪ He was a famous actor once upon a time. ◊Once upon a time is the traditional way to begin a fairy tale.
▪ Once upon a time, there was a beautiful princess named Snow White.
