When I was studying College in the subject of "Project Management" my Professor ask me what is the meaning of ltd in the Company name. I don't really know the answer but the thing is I'm holding my cellphone with Operamini Free Browsing trick and I search for it. Luckily Google saves the day and I see it in Yahoo Answers and Wikipedia.
The abbreviation "ltd" is short for limited, which in business terms means "limited company". This means that the company is private i.e. it does not float its shares on the stock market, in which case its name would change to having "plc" at the end meaning "public limited company".
"Ltd" also distinguishes these companies as having limited liabilities - so that they can only be sued, bankrupted etc as far as the assets of the company and not the total personal assets of the person or people that own the company (as opposed to a "sole trader" where if they are sued they can lose everything).
A limited company is a company in which the liability of the members or subscribers of the company is limited to what they have invested or guaranteed to the company. Limited companies may be limited by shares or by guarantee. And the former of these, a limited company limited by shares, may be further divided into public companies and private companies. Who may become a member of a private limited company is restricted by law and by the company's rules. In contrast anyone may buy shares in a public limited company.
That was a very powerful tool if you have Internet in your class.