Google Spreadsheet: keep lists of your vocabulary in Google spreadsheets. That makes the vocab accessible everywhere through Google Drive. What’s more, you can import the vocab into various flashcard trainers, such as gFlash+ (android and iOS app) and study them anywhere on your phone
Google Translate: Google Translate has gotten much better than it used to be a couple of years ago and now offers a wide range of translations as well as audio. You can save vocab to your phrasebook (1) by starring the translation (3). Tip: chose desired translation from the list first(2). You can also export your phrasebook to a Google spreadsheet (4). That would allow you to quickly import the vocabulary into a flashcard app (see above)
Google Slides: Create your own flashcards. Use the research tool to quickly find images or definitions which you can then drag and drop onto each slide/flashcard.
Google Drive: Use the Google Drive app to store vocab in the form of images or audio files for reference anywhere. You can quickly copy a list of vocab from your textbook with your phone’s camera (the Google Drive app has an inbuilt scanner) and upload it to your Drive. Its easy to find the list again, as Google Drive uses advanced OCR technology. You could also record vocabulary on your laptop/phone as mp3 files and use your phone for revision.
Google Chrome and Google Books: Install the free Google Dictionary extension and you get definitions and pronunciation everywhere on the web. Google Books already has an inbuilt dictionary (the mobile app so far has only phonetic transliteration, whereas the web version comes with audio). If you upload (or import from your Drive) pdf and epub files to Google Books you have a dictionary, translations, annotations and cloud syncing available for vocabulary work.
YouTube: For more visual and auditory learner types there are loads of short videos on various vocabulary areas (from basic colors to advanced business English) on YouTube. Use playlists to organize the videos and to find them quickly when needed.