It feels important to mention David Hume in this context! Hume presents a theory of the mind, and of cognitive content, that he takes to ground a theory of definition and thus of what it means for a term to have and/or lack meaning.
The account is broadly this: we start with perception, and break it down into ideas (thoughts that we have about things) and impressions (which are feelings, seeings, hearings and so on - the distinction, as he puts it, is between thinking about being in pain and actually feeling the pain).
All ideas are ultimately derived from impressions, and so definitions are legitimate ones if we can sketch out the impressions from which an idea associated with a term or concept is derived, and they are illegitimate if not.
So, to speak loosely about Hume's theory, if you can trace a concept back to basic sensations then it is meaningful, and if you cannot then it is meaningless.
Hume's theory of mind, and his concept of definition, does a lot of work in his philosophy and underpins a lot of what ultimately became Logical Empiricism. It's always worth having another re-read of Hume's ideas, particularly if we want to construct more elaborate senses of what human meaning could be.