Imitation isn't flattery. It's Stealing
virtuosovidit.blogspot.com
virtuosovidit.blogspot.com
Both are meaning to denote the direction "up". If you put two mediocre designers in two isolated adjacent booths - they'd come up with the same thing.
This is not stealing. This is an unfortunate coincidence of the lowest common denominators crossing each others paths.
Honestly I feel like the dictionary logo makes little sense to me. I don't see the connection.
While the housing one does due to placement. (It's an obvious roof.)
Sorry, your non-competitor has a different, and better, logo.
I would seriously entertain a possibility of this being a pure coincidence, in which case it's rather unwise to burn bridges and call other guys thieves.
different color scheme / different spelling LookUp vs. LOOK UP / different font /different relative positioning
Basically all they share is the "caret up" symbol and the words Look Up. Both are very common and hardly unique. It can happen that people independently get similar ideas.
We actually once designed a logo after we had redesigned an app. And the logo drew from the app design. We found out a few months later, that there was a hungarian company that had the same name, same concept for logo (which was typography only), very similar font and almost identical color scheme. It can happen. In our case you could blame us for not researching it, but similarities hardly mean stealing, especially if there are no really unique attributes...
edit: corrected syntax, formatting
Also, this looks like one big coincidence.
I think I might have stolen a lot of stuff lately if that's the case.
http://i.imgur.com/L4n6VLM.png
See? It's a totally original, distinctive logo.
I have a few business ideas for him.
IN->PUT
^UPLOAD
>COPYRIGHT
Such clever logos, wow