Something asserted plainly and on the record. A statement can be checked, which is what distinguishes it from a remark.
From state (to declare formally), ultimately Latin status (a standing), with the noun suffix -ment; what is stated is set down firmly enough to be checked, unlike a remark passed in conversation.
Something asserted plainly and put on the record. What distinguishes it from a remark is that it can be checked against what actually happened.