someday

Q: Is it correct to say "I will see you some day."?

No — say "I will see you someday.". As an adverb meaning 'at an indefinite time', it is written as one word; 'some day' as two words usually refers to a specific but unnamed single day.

Definition

adv. at an unknown time in the future. You use this when you talk about a plan or a dream that does not have a set date yet.

adv. at some indefinite time in the future. Often used to express aspirations or hypothetical future events without a specific timeline.

simple

“I hope to visit Japan someday.”

contextual

“She dreams of owning a small house by the sea someday when she retires from her job.”

complex

“While the current technology is limited, scientists believe that someday we will be able to generate clean energy from these deep-sea thermal vents.”

Typically placed at the beginning or end of a clause to set the temporal context.

I will see you some day.

I will see you someday.

As an adverb meaning 'at an indefinite time', it is written as one word; 'some day' as two words usually refers to a specific but unnamed single day.

Univerbation of some + day.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

ADVERB

someday(B1)