Defining the word "bloodbath" as "a battle or fight at which much blood is spilt; a wholesale slaughter, a massacre", the choice was heavily criticised by Twitter users in the wake of the shootings at Sandy Hook elementary school in Newtown, Connecticut on December 14.
"Tasteless and gross," wrote one user. "Seems in very, very poor taste in light of recent events," said another.
The OED, which emails its choice of a word of the day every day has issued a public apology and explanation for picking "bloodbath", the Guardian reported.
"We would like to apologise unreservedly for the publication of bloodbath as the word of the day on 18 December 2012," OED said on its website.
"The OED word of the day is selected months in advance by an editorial committee, and is distributed automatically each day.
"The timing .... Is a coincidence of the worst kind, and we apologise for any distress or upset caused by what might seem to be a highly insensitive choice.
"What we hope to show with our words of the day is that even seemingly commonplace words can have interesting etymologies; however we have taken today's word down from the OED online homepage and are now taking immediate steps to review our scheduling and selection policy," it said.
Twitter users have taken the apology with good grace, the report said.
"Personally, no apology is necessary. I found the linguistic analysis a much-needed step back from the recent horror," said one. "Thanks for the response. Relieved to hear it was an unfortunate coincidence and not intentional," wrote another.
