someday

The word “someday” means at an unspecified time in the future. In plain terms, at some point in the future, though nobody knows exactly when.

Here is “someday” used in a sentence: “She hopes to visit Japan someday.”

“Someday” is an adverb.

“Someday” is a fairly common word in modern English, usually learned at around the A2 level.

Both are correct but mean different things. "Someday" (one word) is an adverb meaning at an unspecified time in the future: "someday I'll travel the world." "Some day" (two words) means one particular but unnamed day: "choose some day next week for the meeting."

Both refer to an unspecified time, but "someday" only points to the future, while "sometime" can refer to the past or the future. "We met sometime last year" is fine; "someday last year" is not. Use "someday" for hopes and plans, and "sometime" when the timing is simply unknown.

No. "Someday" means at an unspecified time in the future, so it cannot describe past events. For an unknown time in the past, English uses "sometime" or "one day" instead: "sometime in the 1990s," "one day last summer."

"Someday" is standard English and grammatically fine anywhere, but it is deliberately vague. In business or academic writing, where commitments need dates, a concrete time frame such as "by 2030" or "within five years" is usually preferred over "someday."