They are both considered synonyms in many literatures, yet there is a subtle difference ,when applying any of them . 'Meaning' is more concerned with what a word ,a phrase or an action directly conveys . What is the meaning of the word "flower" in Spanish ? You wouldn't say here ,what is the 'significance of it . 'Significance' is what a word , a phrase or anything could convey ,refer to in a more indirect way , a message that it could be communicating etc .. What is the significance of this action ? What is the significance of the word ( word x) in this particular context ?

Meaning suggests something more literal and deductive. Significance relates to the importance of the word :)

'Significance' is a common and useful word which means 'importance'. 'Signification' is an extremely rare word. I have never used it my life. In fact, I'll admit that I did a quick check in the dictionary to make sure that it existed. It does, but you can ignore it. I can't think of a single situation in which this word would sound natural, let alone one where it is necessary. Forget you've ever seen it. If you mean 'meaning' just say 'meaning'.