base
The main meaning part of a word. It can be a free base (a word on its own, like form) or a bound base (only found inside words, like rupt).
free base
A base that can stand alone as a word: act, sign, nation.
bound base
A base that is never a word by itself and needs other morphemes: rupt in erupt, struct in construct.
word matrix
A chart that shows a base in the middle with prefixes before it and suffixes after it, to build a word family.
word family
Words that share the same base and are related in meaning: act, action, actor, react.
automaticity
Reading words quickly and accurately without having to slowly sound them out.