siege

siege [siːdʒ]
the surrounding of a fortified place or a city by an armed force in order to compel it to surrender; blockade;
a persistent attempt to gain something;
(obsolete) a seat or throne.
to siege = to lay siege to = to besiege

useful resources:

http://www.oxforddictionaries.com/
http://dictionary.cambridge.org/
http://www.wordreference.com/
http://www.merriam-webster.com/