Absorbed by first item, missing fourth item (4)
I believe the answer is:
into
'absorbed by' is the definition.
(I've seen this in another clue)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for into that I've seen before include "digging" , "Fascinated by" , "To a position inside" , "Teachers' trade union" , "Enthusiastic about" .)