I want to remove the serach option from my menu?

Hi,

I’m using a customized twentyeleven theme on the website https://noelleokeeffe.com/ I’m revamping this website as part of a college work placement assignment.
I want to remove the search option from the menu completely. I have looked at the old forums but the advice is not working for me! I hope someone out there can help! Thanks.

Tara