Facing a lunar eruption, find something everyone can grasp (6,6)

I believe the answer is:

lingua franca

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'can grasp' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'facing a lunar eruption find something everyone' is the wordplay.
'facing a lunar' anagrams to 'LINGUA FRANCA'.
Though, I'm not sure how this is indicated.

Can you help me to learn more?

(Other definitions for lingua franca that I've seen before include "Hybrid medium of communication" , "Common language" .)

I've seen this clue in The Irish Times.

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