What is an Endocrine Gland?

An endocrine gland is a set of cells that secrete hormones directly into the blood. An example would be the pituitary gland.
Another type of gland is an exocrine gland but these use ducts to secrete substances out into the body. I like to remember this by exo needs an exit which is the duct and endo is at the end so goes directly into the blood.