Swiftでシステム内蔵辞書を検索する方法 ref: http://qiita.com/doraTeX/items/9b290f4e39f1e100558b

DictionaryServiceManager-Test.swift

let wisdomPath: String
if #available(OSX 10.13, *) {
    wisdomPath = "/System/Library/Assets/com_apple_MobileAsset_DictionaryServices_dictionaryOSX/65c5f4f22827dba6b0a6bc85755863317890953b.asset/AssetData/Sanseido The WISDOM English-Japanese Japanese-English Dictionary.dictionary"
} else {
    wisdomPath = "/Library/Dictionaries/Sanseido The WISDOM English-Japanese Japanese-English Dictionary.dictionary"
}

// "swift" の意味を取得
let word = "swift"
if let content = DictionaryServiceManager().lookUp(word, inDictionary: wisdomPath) {
    print(content)
} else {
    print("NOT FOUND")
}

DictionaryServiceManager.swift

import Foundation

class DictionaryServiceManager {
    private let AppleGlobalDomainName = "Apple Global Domain"
    private let DictionaryServicesKey = "com.apple.DictionaryServices"
    private let ActiveDictionariesKey = "DCSActiveDictionaries"
    
    private var globalDomain: [String : Any]? {
        return UserDefaults.standard.persistentDomain(forName: AppleGlobalDomainName)
    }
    
    private var dictionaryPreferences: [String : AnyObject]? {
        return self.globalDomain?[DictionaryServicesKey] as! [String : AnyObject]?
    }
    
    private var currentDictionaryList: [String]? {
        return self.dictionaryPreferences?[ActiveDictionariesKey] as! [String]?
    }
    
    private func setUserDictPreferences(_ activeDictionaries: [String]) {
        if var currentPref = self.dictionaryPreferences {
            currentPref[ActiveDictionariesKey] = activeDictionaries as AnyObject
            if var gDomain = self.globalDomain {
                gDomain[DictionaryServicesKey] = currentPref
                UserDefaults.standard.setPersistentDomain(gDomain, forName: AppleGlobalDomainName)
            }
        }
    }
    
    func lookUp(_ word : String, inDictionary dictionaryPath : String) -> String? {
        let currentPrefs = self.currentDictionaryList
        self.setUserDictPreferences([dictionaryPath])
        
        let range = CFRangeMake(0, word.utf16.count)
        let result = DCSCopyTextDefinition(nil, word as CFString, range)?.takeRetainedValue() as String?
        
        if let currentPrefs = currentPrefs {
            self.setUserDictPreferences(currentPrefs)
        }
        
        return result
    }
}