It is a bit more than that. 'jna' is the root and when 'vi' is added it signifies 'division'. But vijnana has two aspects one a knowledge at mundane level and another at supermundane level, where it approaches prajna a and eventually remains as plain jnana -- knowledge without division.
I see, thankyou.
I was getting this from my translation of the Bhagavad Gita, which is translated by Eknath Easwaran and has commentary by him and by Diana Morrison.