(idiomatic) Finally, permanently, conclusively.

One generation apart.

(computing) of a type of storage technology in which data, once written, cannot be erased or modified

(idiomatic) Unexpectedly; without warning; all of a sudden. / Used other than figuratively or idiomatically: All at the same time; all together.

(idiomatic) Occasionally; sometimes.

A quick clean or polish. / A cursory inspection or survey.

Likely to happen only once in one's lifetime.

(idiomatic) Again, once more, one more time.

Alternative spelling of once-over

Misspelling of one at a time.