The centriole is a specific part of animal cells.
The centriole is a hollow cylindrical structure containing nine triplets of microtubules surrounded by many other proteins. A centriole is occasionally bound perpendicular to a second centriole to form a centrosome.
The centriole is the starting point for polymerisation of tubular proteins to form microtubules (cytoskeleton). The centrioles are therefore found at the base of cilia and flagelli where microtubules are important due to their shape.
Centrioles are also involved (in the form of a centrosome) in the formation of mitotic spindles during cell division.
The centriole is a structure composed of nine triplets of microtubules. © Louisa Howard, Miguel Marin-Padilla, Wikimedia, public domain