Container

Here are some of the various containers in Tcl:

array
A container of variables, keyed by name
dict
The standard key-value store. Values are ordered by the sequence in which they were set
dictionary, by Frederic Bonnet
an implementation of a key-value store, that preceded dict
list
The standard container for sequences of values
vector (BLT)
one-dimensional arrays of values
TclX keyed lists
NAP
has some sort of array/vector data structure.