What makes a brother german?

I haven't found time to write long blog entries lately, so I'm going to try a different approach -- more frequent short posts highlighting miscellaneous items of interest that I come across in my research. The first of these posts is below:
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I was recently reading some old Scottish records and came across the phrase "Duncan Campbell, brother german of Archibald Campbell of Inveraw." I was pretty sure they weren't referring to a German brother in a Scottish family, but beyond that I wasn't sure what the term meant. A little Googling revealed that brother-german simply refers to a full brother who shares both parents (as opposed to a half-brother). This usage of "german" shares a common origin with "germane", which means closely related.  Of course you could have German brothers-german......