fit on the back of a postage stamp

fit on the back of a postage stamp

Fit in a very small space, because there is very little content. This phrase is used to indicate that one knows very little about something. The idea is that one could only fill a very small space—like the back of a postage stamp—writing what one knows about the topic. I am definitely going to fail this test—what I know about Victorian poetry could fit on the back of a postage stamp!
See also: back, fit, of, on, postage, stamp
References in periodicals archive ?
What we know about Pluto today could fit on the back of a postage stamp," said Colleen Hartman, a NASA administrator.