Yes, wekipedia can be downloaded and used for offline reading and reference.
One of the way is wiki taxi, It is a software which enable you to access wikipedia offline. Also it has multilingual feature to enable you to read in your desired language. It is always up to date(with a difference of few weeks).
Another option is Kiwix. Kiwix is an offline reader for Web content. It’s especially intended to make Wikipedia available offline (see features). This is done by reading the content of the project stored in a file format ZIM, a high compressed open format with additional meta-data.Kiwix is a free software, that means you can freely copy, modify and spread it. Check in here to download this software kiwix.