An umbrella term is a word or phrase that covers a wide range of concepts belonging to a common category. For example, cryptology is an umbrella term that encompasses cryptography and cryptanalysis, among other fields. Similarly, an umbrella organization is a central and coordinating body representing a number of smaller, separate bodies.
A blanket term is a closely related word or phrase that is used to describe multiple groups of related things. The degree of relation may vary or have a minimal relationship, but blanket terms often trade specificity for ease of use. In other words, a blanket term, by itself, gives little detail about the things that it describes or the relationships between them, but it is easy to say and remember. Blanket terms may originate as slang but eventually become integrated into the general vocabulary.
Glaucoma is a broad term for a number of different conditions that damage the optic nerve