SUBGROUP
subgroup
(noun) (mathematics) a subset (that is not empty) of a mathematical group
subgroup
(noun) a distinct and often subordinate group within a group
Source: WordNet® 3.1
Etymology
Noun
subgroup (plural subgroups)
A group within a larger group; a group whose members are some, but not all, of the members of a larger group.
(group theory) A subset H of a group G that is itself a group and has the same binary operation as G.
Synonyms
• (group within a group): subset
Verb
subgroup (third-person singular simple present subgroups, present participle subgrouping, simple past and past participle subgrouped)
To divide or classify into subgroups
Source: Wiktionary
Sub"group`, n. (Biol.)
Definition: A subdivision of a group, as of animals. Darwin.
Source: Webster’s Unabridged Dictionary 1913 Edition