Lilac is a flowering plant that is part of the olive family and is known for its fragrant PURPLE, MAUVE, and white flowers. It is also known as a SHRUB, which is a woody plant with multiple stems that can reach up to 10 feet in height. The term 'lilac' is used to describe the color of the flowers, which range from light PURPLE to deep MAUVE. The term can also be used to describe the SHRUB itself, which has a distinctive shape and is often used in landscaping.