Induced fit refers to an enzyme's conformation and shape-changing over time in response to substrate binding.
As a result, the enzyme becomes catalytic, lowering the activation energy barrier and increasing the overall rate of the reaction.
Example:
Adenylate kinase is an example of induced fit.
When the enzyme's essential substrates, NMP (Nucleoside monophosphate) and ATP (Adenosine triphosphate), are bound, it changes its conformation somewhat.