1. A thin short line, a line (in a drawing, drawing, etc.).
2. A separate detail, a characteristic moment of something.
Electronic dictionary Lingvo
In a black and white caricature, the “stroke” is important, because it gives a graphical intelligibility to the image, which is necessary for quickly perceiving the meaning of the plot.
Also, in the case of poor-quality printing or a strong reduction in printing, is a special condition for the artist. Often, the feature of hatching in the figure expresses the individual handwriting of the artist and, importantly, makes his drawings recognizable.