The phrase "half a glass" is correct and usable in written English.
You can use it when referring to a partial amount of liquid. For example, "I'm only going to have half a glass of wine with dinner."
"Half a glass," Humm says, laughing.
Rabaey would reward them with half a glass of cola.
Hadley poured herself half a glass of wine.
I'll have half a glass of red wine before bed.
Many females, for example, confine themselves to one glass per meal or even half a glass".
Deglaze with a squeeze of lemon and half a glass of white wine.
"Do you drink?" "Oh, hardly ever -- maybe a half-a-glass of red wine on very specials occasions -- like weddings -- or a coronation".
So I started to turn that bright light of awareness on myself while I was slightly tipsy or even if I'd just had a half-a-glass of wine.
Pour the beer half full into a glass.
It depends on if you're a "glass half empty/glass half full" person, I suppose.
It may depend whether you're a glass half full, or glass half empty type.
