/oh mish"euhn/ , n.
1. the act of omitting.
2. the state of being omitted.
3. something left out, not done, or neglected: an important omission in a report.
[ 1350-1400; ME omission- (s. of omissio ), equiv. to omiss ( us ) (ptp. of omittere to let go; see OMIT) + -ion- -ION; see MISSION ]