Deltoid
Deltoid (delta-shaped) can refer to:

The deltoid muscle, a muscle in the shoulder
Kite (geometry), also known as a deltoid, a type of quadrilateral
A deltoid curve, a three-cusped hypocycloid
A leaf shape
The deltoid tuberosity, a part of the humerus
The deltoid ligament, a ligament in the ankle

See also
Delta (disambiguation)
The Deltoid Pumpkin Seed (1973), a book by John McPhee