Meaning of “shift” - Learner’s Dictionary

shift

noun [ C ] uk us /ʃɪft/
CHANGE

a change in something:

There has been a dramatic shift in public opinion on this matter.
WORK

B2 a period of work in a place such as a factory or hospital:

He works an eight-hour shift.
COMPUTER (also shift key)

the key on a computer keyboard which allows you to create a capital letter (= a large letter of the alphabet used at the beginning of sentences and names)

(Definition of “shift noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)