Null has several synonyms depending on context, primarily conveying the idea of nothingness, invalidity, or lack of effect.
Adjective (having no value or force): void, invalid, nugatory, ineffective, useless, futile, fruitless, worthless, unavailing, null and void.
Adjective (lacking distinctive qualities): empty, blank, characterless, colorless, vacuous, insipid, vapid, expressionless.
Noun (zero or nothing): zero, nil, nothing, zilch, zip, nada, cipher, aught, goose egg, naught.
In computing, null often means "no value" or "undefined," where synonyms include *undefined, unassigned, absent*. In legal contexts, null and void is a common phrase, with synonyms like invalidated, annulled, canceled, revoked, repealed.
'null' is qualitative, representing the absence of quantity. Closer to the word 'void' than the number 'zero'. Example: he reduced it to nil.
'zero' is quantitative. Example: he got zero on his exam.
No, they are not the same.
In an everyday language context, 'null' can mean that something is meaningless, as in:
The agreement became null when Sam failed to fulfill his side.
In a programming/data context (though I still think this is a language question, rather than a programming question), 'null' can mean the absence of information. If you are wondering how many apples there are, 'null' means 'I don't know'. 'Zero' means that you know that there aren't any apples.
Zero always refers to a quantity.