A metal lump is a solid piece of the material with no defined shape. Gallium bonds easily with most metals and is commonly used to make low-melting alloys. It is one of four metals (including mercury, rubidium and caesium) that are liquid at or near room temperature. This means that if you were to pick up a lump of gallium, the warmth of your hand would melt it. Once you set it down again, it will go back to its solid form.
A Gallium lump, combined with arsenic is used to make Gallium arsenide, which has been touted as a possible replacement for Silicon.