The basic premise here then is that as there is no empirical evidence for a concrete thing called time, then it is merely a word; and as such its meaning can be wholly ascribed to the way we (its originators) determine. So let’s look in the dictionary.
The dictionaries aren’t clear on the matter of time, they all have very varied (and often, frankly, unsatisfactory) definitions, and sometimes even seem to have abandoned the attempt to define it succinctly and instead merely document its many varied uses, thus obfuscating the primary definition(s) with secondary, figurative and colloquial uses. Also, time is used in many expressions, and the context or use of the expression becomes the definition.
As an example, Merriam-Webster offers this (amongst other definitions) :-
“a nonspatial continuum that is measured in terms of events which succeed one another from past through present to future”. (https://www.merriam-webster.com/dictionary/time). Some of this I sort of get, but “Nonspatial continuum”…any ideas anyone?
Some of the definitions are repetitious, some ambiguous and some circular (circular meaning that time is defined with reference to itself or words that are themselves dependent on time (‘period’ for instance) – it happens a lot with time. Or they make vague reference to too many other factors (as varied as ‘existence’, ‘the universe’ and ‘everything’).
However, a little analysis will show that we can lead to a few rational conclusions about the word, and its definitions.
It’s definition as some kind of measurement would seem to be the commonest definition that has some agreement (though even then, it isn’t always clear what it is measuring).
What is hard to find are root definitions of time that are derived externally i.e., outside time itself, and that are succinct and clear.