Note: in BRIT, also use 'cognisance'
1.
If you take ~ of something, you take notice of it or acknowledge it. (FORMAL)
The government failed to take cognisance of their protest.
= acknowledge
PHRASE: V inflects
2.
Cognizance is knowledge or understanding. (FORMAL)
...the teacher’s developing ~ of the child’s intellectual activity.
N-UNCOUNT: oft N of n