Meaning of “substance” - Learner’s Dictionary

substance

noun uk us /ˈsʌbstəns/
MATERIAL [ C ]

B2 a solid, liquid, or gas:

a dangerous substance
illegal substances (= illegal drugs)
TRUTH [ U ]

truth or importance:

There's no substance to the allegations.
the substance of sth

the most important part of what someone has said or written

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