xadba -xab- gismu

x1 is exactly/approximately half/semi-/demi-/hemi- of x2 by standard x3.

See also mulno, pagbu.

In notes:

mulno
x1 (event) is complete/done/finished; x1 (object) has become whole in property x2 by standard x3.
pagbu
x1 is a part/component/piece/portion/segment of x2 [where x2 is a whole/mass]; x2 is partly x1.
fi'ure (comp!)
half.
pimu (comp!)
half.
bolxadba
xa1 is a hemisphere of sphere b1=xa2, of material b2, halfness standard xa3.
plinyxabykoi
k1 is the equator of planet x2=p1 (default Earth) revolving around p2
plinyxadba
x1 is a hemisphere of planet x2 (default Earth) revolving around p2
xabycinse
c1 exhibits demisexuality in situation c2 by standard c4.
xaby'efku
x1=xadba1=efku1 is an exact/approximate half of a half of a half... of x2=xadba2=efku2, cut in half exactly x3=efku3 times, by standard x4=xadba3
xabyxadba
x1 is exactly/approximately a quarter of x2 by standard x3.
debrpisu
d1 is a pea from plant [legume] of species Pisum sativum of variation/variety/cultivar d2.