A statue was a sculpture of a life-form, normally of its entire body.
A Melkur was an evil creature immobilised by the tranquil nature of Traken. Over time they turned into statues and disintegrated. The Master's TARDIS disguised itself as a Melkur as part of his plan to take over the Source. (TV: The Keeper of Traken)
During the Year That Never Was, the Master had an immense statue of himself built as he ruled over the Earth. When the destruction of the paradox machine caused time to reverse, the statue and the year was erased from history. (TV: Last of the Time Lords)
A giant statue of a human was being carved out of gregarian rock on the Ark during its 700-year journey to Refusis II, but was given a Monoid head when they took over. Monoid One had a fission bomb planted in the statue's head to destroy the Ark and the human passengers, but it was thrown out of the launching bay by a Refusian. (TV: The Ark)