Yuck. Let’s make that better! On the Mac, the place you’ll change that setting is within System Preferences > Sharing.
At the top of that pane, there’s a box for you to type in.
Then to change this on the iPhone or iPad, visit Settings > General > About. You can edit your device’s name at the very top (and while you’re there, you can also see all sorts of stats about what’s taking up your space!).
Anyway, once you update that info, iCloud.com (and the Find My iPhone app) should reflect the change within a few minutes.
Ah, that’s much better! I mean, I don’t have a ton of devices myself, but I have seen families with ten or fifteen items clogging up this list. Trying to discern which one was missing if they all had generic names would be…less than ideal. Let’s put it that way.
This tip was suggested by the ever-brilliant Bryan Mahler.