petition
Concise Oxford English Dictionary © 2008 Oxford University Press:
petition/pəˈtɪʃn/
▶noun
- 1 a formal written request, typically signed by many people, appealing to authority in respect of a cause.
■ an appeal or request.
- 2 Law an application to a court for a writ, judicial action in a suit, etc.
– derivatives
petitionary adjective,
petitioner noun.
petitionary adjective,
petitioner noun.
– origin ME: from L. petitio(n-), from petit-, petere ‘aim at, seek, lay claim to’.
'petition' also found in these Oxford entries:

