Dictionary support

Frans de Jonge edited this page Sep 8, 2018 · 16 revisions

KOReader supports dictionary lookup in EPUB and even in scanned PDF/DJVU documents. All you need to do to select a phrase for the dictionary and Wikipedia is hold on a word, or hold and drag to select multiple words for other functions.

Dictionary lookup

In order to use the dictionary lookup function, you first need to install one or more dictionaries in the StarDict format. A list of freely available dictionaries can be found on the Firedict site. (Firedict "is a simple offline dictionary software for Firefox OS with support for the StarDict format.")

The dictionaries need to be installed into one of those directories:

  • /sdcard/koreader/data/dict directory for Android
  • koreader/data/dict directory for Kindle
  • .adds/koreader/data/dict/ directory for Kobo
  • applications/koreader/data/dict directory for Pocketbook

The StarDict format dictionary files have suffixes *.idx, *.ifo or *.ifo.gz, *.dict or *.dict.dz.

HTML encoding within StarDict dictionaries supported

You can use HTML encoded dictionaries, as described here.

Also, dictionaries could be tweaked with custom css file, as described here and here. You can find sample files how to tweak them here. And some more discussion can be found here.

Converting from other sources

Some freely available dictionaries can be converted to the StarDict format with stardicter. See also wiktionary-to-stardict.

You may also be able to use DICT files used by the standard dictd daemon and the related dict packages that contain .dict files. Those files can be converted to stardict format using the /usr/lib/stardict-tools/dictd2dic command provided in the stardict-tools package, although it seems to fail to create the necessary metadata files like the .ifo file.

Dictionary lookups in scanned pages

KOReader has a build-in OCR engine for recognizing words in scanned PDF/DJVU pages. In order to use OCR in scanned page, you need to install tesseract trained data for your document language.

  • install Tesseract language data
    • copy language data files for Tesseract 3.02 (e.g. eng.* in tesseract-ocr-3.02.eng.tar.gz for English and spa.* in tesseract-ocr-3.02.spa.tar.gz for Spanish) into koreader/data/tessdata

Tips and tricks

To open word in dictionary, press and hold. But, press and hold for more than 3s, it opens menu with more options, as described here.

Dictionary supports history of searched words, accessible through menu. More info can be found here (with images).

You can cancel (too) long, or any, search by tap. More on this here.

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