picked up an extension?

Could you tell me what extension means in this sentence, please?

Jonah picked up an extension and they chatted for a while about the settlement conference --who was there, where was it, what was it like?

I understand that you can dial an extension but how can you one up?

Thanks a lot,
Torsten[YSaerTTEW443543]

TOEIC listening, photographs: Subway tunnel[YSaerTTEW443543]

“Pick up the extension” means “pick up the additional telephone set that is connected to the same telephone line”. It’s a very common expression.

.
Still looking for additional examples of Grisham’s use of the word ‘fetch’, Torsten? :wink:

This link confirms what Molly posted:
dictionary.cambridge.org/define. … &dict=CALD
.