Meaning of “cubic” - Learner’s Dictionary

cubic

adjective uk us /ˈkjuːbɪk/
cubic centimetre/inch/metre, etc

a unit of measurement that shows something's volume (= length multiplied by width multiplied by height) :

The reservoir holds 22 million cubic metres of water.

(Definition of “cubic” from the Cambridge Learner’s Dictionary © Cambridge University Press)