Latest of many met up, then dispersed (9)

I believe the answer is:

umpteenth

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'latest of many' is the definition.
I can't judge whether this defines the answer.

'met up then dispersed' is the wordplay.
'dispersed' is an anagram indicator.
'met'+'up'+'then'='metupthen'
'metupthen' is an anagram of 'UMPTEENTH'.

Can you help me to learn more?

(Other definitions for umpteenth that I've seen before include "Nth" , "such an unspecified time?" , "Latest or last of very many" , "being so late in ordering" , "Latest of goodness knows how many" .)

I've seen this clue in The Times.

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