Acorn
Acorns were the seeds of oak trees. (TV: The Android Invasion [+]Loading...["The Android Invasion (TV story)"], In the Forest of the Night [+]Loading...["In the Forest of the Night (TV story)"])
In 2050, by which time oak trees were extinct, a Centuripede gave acorns from Robin Hood's time to Starkey and K9. (TV: The Last Oak Tree [+]Loading...["The Last Oak Tree (TV story)"])
On Albert, Christina Morgenstern was given three golden acorns which could grant wishes by the wodewose when she answered his riddles. (PROSE: Grimm Reality [+]Loading...["Grimm Reality (novel)"])
In the far future, Hade believed that "there's one rotten acorn in every barrel" was an old Earth saying. (TV: The Sun Makers [+]Loading...["The Sun Makers (TV story)"])
They could be used in coordinates. In the 51st century, River Song gave her coordinates as "triple-7 5/349910012/acorn". (TV: The Time of Angels [+]Loading...["The Time of Angels (TV story)"])