Submitted by György Chityil ... on Fri, 01/19/2018 - 18:28 Hierarchy: AbbreviationDescription: {{US|army|aviation}} Prefix code for observation helicopter designations.Ngram: OHNgram Text: OHSource: WiktionaryIssue: 0Wiktionary tag: ArmyaviationNgram Count: 1Wikokit WikiText ID: 126779