Lobe (noun)

1. A projecting part of an organ or other structure in the body, typically one of a pair.
2. A rounded or flattened projection on a leaf, petal, or other organ.

Origin:

Late middle english: from latin lobus "lobe", from lobus "pod, husk".

Examples:

1. The lungs have three lobes on each side.
2. The brain has two lobes, the cerebrum and the cerebellum.
3. The leaf has five lobes.
4. The petals have three lobes.
5. The liver has four lobes.