Among the easily installable and ad-free apps within the PureOS store is Dictionary. This is a simple tool that lets you search through numerous online or local dictionaries and translation sources.
After install, the defaults are perfectly suitable for most users to look up data online:
For those that want to become invisible; you can air gap your Librem 5 from all networks while still using self-hosted services like translation. To install locally hosted dictionary services run the following commands:
sudo apt install dictd
sudo apt install dict-gcide
sudo systemctl start dictd
sudo systemctl enable dictd
If you’d like a few extra dictionaries to look up data in:
sudo apt install dict-freedict-eng-*
You’ll also want to point the Dictionary app at your new service:
Not only can the Librem 5 locally host and use Dictionary services, but it can share the service with your network. To do this, edit /etc/dictd/dictd.conf to accept non-local connections.
Lookup what you need to, and keep your data in your control.