kijno -kij- gismu

x1 is a quantity of/contains/is made of oxygen (O); [metaphor: supporting life/combustion].

See also jelca, vacri, vasxu.

In notes:

jelca
x1 burns/[ignites/is flammable/inflammable] at temperature x2 in atmosphere x3.
vacri
x1 is a quantity of air/normally-gaseous atmosphere of planet x2, of composition including x3.
vasxu
x1 breathes/respires x2 [gas].
tabrelkijno
x1 is a quantity of carbon dioxide (CO₂)
tabypavykijno
x1 is a quantity of carbon monoxide (CO)
rakle
x1 is an atomic element in group x2 [usually, vertical column; denotes electron configuration and, thereby, chemical similarity with vertical neighbors] and period x3 [usually, horizontal row; denotes similarity in size with horizontal neighbors, as well as having the same number and type of electron shells as them] and belonging to other 'class'/'category'/'type'/having other properties x4 according to scheme/organization pattern/standard/periodic table x5.
ratniklesi
x1 is an atomic element in group x2 [usually, vertical column; denotes electron configuration and, thereby, chemical similarity with vertical neighbors] and period x3 [usually, horizontal row; denotes similarity in size with horizontal neighbors, as well as having the same number and type of electron shells as them] and belonging to other 'class'/'category'/'type'/having other properties x4 according to scheme/organization pattern/standard/periodic table x5.