a ketone / any similar compound containing a carbonyl functional group

Belonging to one.

Contraction of one is.

plural of one / (sports) A senior or first team (as opposed to a reserves team). / (UK, prison slang) The cells located on the ground floor.

plural of one / Obsolete form of one's.

(uncountable) State of being one or undivided; unity. / (countable) The product of being one or undivided.

(chiefly Britain, Commonwealth of Nations except Canada, Ireland) Alternative form of no one

Not any person or thing whatsoever.

(colloquial) A particularly special or compatible person or thing. / (colloquial) A particular person destined to save the universe or world; the chosen one.

The person or thing.