PROPERSUBSET
proper subset
Noun
- Of a set, a set that is a subset of the set but not equal to it.
- {2, 4, 5} is a proper subset of {1, 2, 3, 4, 5}, but {1, 2, 3, 4, 5} is not.
The above text is a snippet from Wiktionary: proper subset
and as such is available under the Creative Commons Attribution/Share-Alike License.