sub·set 
/ˈsʌbˌsɛt/ noun
plural sub·sets /ˈsʌbˌsɛt/ noun [count] technical : a group of things, people, etc., that is part of a larger group
▪ The set {1,2,3} is a subset of the set {1,2,3,4,5}. ▪ Only a small subset of the patients in the study experienced these side effects.
▪ The set {1,2,3} is a subset of the set {1,2,3,4,5}. ▪ Only a small subset of the patients in the study experienced these side effects.
