Well, once I could mathematically and scientifically precisely measure the volume and density of the liquid (assuming it IS a liqud) and it's ratio to the parameters of said glass,........I could easily answer that question for you. Most likely it would be something like this......"Well Jen, based on my observation along with simple chemistry, alchemical formulations and transitional physics and calculations,..that glass is actually 48.024% full to its maximum capacity so, it is actually LESS than half of either!
Then I would be expected to be asked to leave the premises and to never return....of which wouldn't bother me so much because I would have thought she would have done her homework prior to asking such a vague question to begin with!
Oh yeah, ...who cares anyway?