What term includes words and parts of words?

Is there a single term which includes words and parts of words, e.g., the term could be applied to any of these:

• the word “international”
• the root “inter-” taken independently of the words it fits in
• any segmentable part of a word, e.g. “in”, “ter”, “na”, “tion”, “al”, which is in this case segmentation by syllable

The term could, but need not necessarily, include letters.

Solution 1:

It depends on whether the word chunk is a meaningful constituent or not. Most chunks aren't.

In international, there are at least three Morphemes -- maybe four, depending on whether one counts the in- in inter:

• in-ter . nation . al

Morphemes are the meaningful chunks of words, like book and keep in bookkeepers, as well as derivational and inflectional bound forms like -al, -er, and -s.

However, meaningless substrings such as terna, ookkee, or nal are not morphemes.