pivotal

US /ˈpɪv.ə.t̬əl/
UK /ˈpɪv.ə.t̬əl/
"pivotal" picture
1.

of crucial importance in relation to the development or success of something else

:
•
The discovery of penicillin was a pivotal moment in medicine.
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Her role in the project was absolutely pivotal.
:
crucialcriticalcentralkeyvitalessentialdecisivemomentousimportantsignificant