Pop-up translators for Macbook Pro

Hi all, I've recently acquired my first Apple laptop and wondered if anyone can recommend a pop-up (mouse over) translation tool.  I have always used Lingoes on my Windows laptops in the past, but they don't seem to have a Mac OS version.  Any guidance appreciated.  Fair to say I'm still at the stage where everything feels wrong - having never touched an apple laptop product before!! but am getting used to it gradually.