DOC, DOCX, PDF, EPUB, ODT, CHM,....

There were many formats of documents created over years, ISTQB provides own glossary in PDF format. I decided to convert it some time ago to form of Android application: https://play.google.com/store/apps/details?id=com.mwiacek.istqb.glossary. You can search topics, jump to related topics, etc. Small, fast, effective.