Collection type 

A collection column is declared using the collection type, followed by another type.

A collection column is declared using the collection type, followed by another type, such as int or text, in angle brackets. For example, you can create a table having a list of textual elements, a list of integers, or a list of some other element types.

list<text>
list<int>

Collection types cannot be nested, but frozen collection types can be nested inside frozen or non-frozen collections. For example, you may define a list within a list, provided the inner list is frozen:

list<frozen <list<int>>>

Indexes may be created on a collection column of any type.

Using frozen in a collection 

A frozen value serializes multiple components into a single value. Non-frozen types allow updates to individual fields. Cassandra treats the value of a frozen type as a blob. The entire value must be overwritten.

column_name collection_type<data_type, frozen<column_name>>

For example:

CREATE TABLE mykeyspace.users (
  id uuid PRIMARY KEY,
  name frozen <fullname>,
  direct_reports set<frozen <fullname>>,     // a collection set
  addresses map<text, frozen <address>>     // a collection map
  score set<frozen <set<int>>>              // a set with a nested frozen set
);