Items

In Dota, Items can be divided into many categories...

Movement speed items:
Items which help in increasing your movement speed (ms) such as boots of Travel, Power treads, yasha, Eul's scepter of divinty, these items gives permanent movement speed while other items like lothar's Edge and phase boots gives bonus movement speed and a special ability.

Damage items:
These items basically bought to strength and agility heroes to increase their damage and lifesteal -if present- and so making them even harder to be killed.
Example of these items are: Divine Rapie, Buriza-do Kayanon, Monkey King Bar, Radiance, Battle Fury,... etc.

Agility items:it is called so because besides its ability -whatever was- it helps in increasing your agility giving' you more powerful hero, It includes Sange & Yasha, Manta Style, The Butterfly,...

Intelligence items:Besides its ability, It increases your mana pool, It includes Guinsoo, Aghnam, Shiva's guard, Orchid, Dagon, Blood stone,....

*There are many much items can be used at any type of hero you have, When buying the item consider its use for you and its efficiency against your enemy too.