GNU Collaborative International Dictionary of English

Found one definition

1.       
   Omission (?), n. [L. omissio: cf. F. omission. See Omit.]
   1. The act of omitting; neglect or failure to do something required by propriety or duty.
   
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   The most natural division of all offenses is into those of omission and those of commission. Addison.
   
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   2. That which is omitted or is left undone.
   
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