Noun
Penny Black (plural Penny Blacks)
(philately) The world's first official postage stamp, issued in 1840 in the United Kingdom as part of postal reforms.
Muir, Douglas N, Postal Reform & the Penny Black, National Postal Museum, 1990, p.42 This first edition was marked "private and confidential," and was not released to the general public. Source: Internet
When the time comes for her to undergo a near-fatal "conversion" into the Amazonian ranks, she escapes, aided by Penny Black, who is wounded by Artemis in the process. Source: Internet