What is meant by SUNION and SINTER?

SUNION : The members of the set are returned from the union of all the sets that are given.
 
SINTER : The members of the set are returned that result from the intersection of all the sets that are given.

Example :
127.0.0.1:6379> SMEMBERS TEST_KEY_A

1) "1"

2) "2"

3) "3"

127.0.0.1:6379> SMEMBERS TEST_KEY_B

1) "2"

2) "6"

127.0.0.1:6379> SUNION TEST_KEY_A TEST_KEY_B

1) "1"

2) "2"

3) "3" [prints union of two sets]

4) "6"

127.0.0.1:6379> SINTER TEST_KEY_A TEST_KEY_B

1) "2" [print intersection of two sets]