an obsolete word of French origin meaning "blood", but in the sense of "noble birth". For example "I am of royal
sanguage, you unworthy
oaf".
It remains to be determined whether the word, clearly coming ultimately from the Latin sanguis (gen. sanguinis), entered English during the Norman conquest (along with words like veal and beef), or much later on, possibly a latinate coinage.
No credit can be given to the theory that considers "sanguage" as a fossil Latin word, dating back to the Roman conquest of Britain.
More information can be found in
pseudoetimology