If it is stated that you will be able to host Multiple Domains with a
web hosting package then it means that you can host more than 1 or say, a number of Domain names with/under the hosting package. If it is mentioned that you will be able to host 10 domains with the hosting package then you will be able to host only 10 domains with/under the respective hosting package. You should select the web hosting package according to the domains you have and if possible, select a web hosting package with unlimited domains so that you can host more domains in future without upgrading your package.