One day, some day (especially in warning of a negative consequence).

plural of one-two

(idiomatic) Having only one opinion, outlook, tone, etc., especially as expressed repetitively; without variety or range.

plural of turn-on

plural of roll-on

(idiomatic, colloquial) Used to express the speaker's belief that a preceding statement expressed a desired rather than an actual state of affairs.

In one's thoughts, especially persistently or recurrently. / Causing worry or preoccupation.

plural of all-in-one

A multifunction device, especially a printer that also works as a scanner and fax machine. / (computing) A desktop computer having all major components, including the display, built into a single unit.

Combining two or more items in one unit.