To make a broad statement or conclusion based on specific cases or instances. It's not fair to generalise about all teenagers based on the actions of a few.
To apply something, such as a concept or rule, to a wider range of situations or cases. The teacher encouraged the students to generalise the mathematical principle to solve different types of problems.
To spread so as to affect the whole of something; to become widespread or diffused. The infection quickly generalised and affected multiple organs.