Last-minute race participant

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Postentry \Post"en*try\, n. [Pref. post- + entry.] A second or subsequent, at the customhouse, of goods which had been omitted by mistake. (Bookkeeping) An additional or subsequent entry.

Wiktionary Word definitions in Wiktionary
a. After entry into anything. n. An additional or subsequent entry, of as mistakenly omitted goods in a customs report.