The word is the fundamental unit of language. It is a dialectical unity of form and content.

Morphemic structure of words

There are two levels of approach to the study of word- structure: the level of morphemic analysis and the level of derivational or word-formation analysis. It has been universally acknowledged that a great many words have a composite nature and are made up of morphemes, the basic units on the morphemic level, which are defined as the smallest indivisible two-facet language units.

The four types (root words, derived words, compound, shortenings) represent the main structural types of Modern English words, and conversion, derivation and composition the most productive ways of word building.

According to the number of morphemes words can be classified into monomorphic and polymorphic. Monomorphic or root-words consist of only one root-morpheme, e.g. small, dog, make, give, etc. All polymorphic word fall into two subgroups: derived words and compound words – according to the number of root-morphemes they have. Derived words are composed of one root-morpheme and one or more derivational morphemes, e.g. acceptable, outdo, disagreeable, etc. Compound words are those which contain at least two root-morphemes, the number of derivational morphemes being insignificant. There can be both root- and derivational morphemes in compounds as in pen-holder, light-mindedness, or only root-morphemes as in lamp-shade, eye-ball, etc.

The morphemic structure of the word is being established by the method of immediate and ultimate constituents (непосредственных и конечных составляющих). This method is based on a binary principle which means that at each stage the word is broken into the components (immediate constituents) after that these components are broken further into two other components. When the components can't be further divided and the analysis is completed we have arrived at the ultimate constituents — the morphemic structure of the word.
Friend-ly-ness

Pseudo- morphemes – sound clusters recognized as morphemes but lack lexical meaning of their own, they are set apart from all other types of morphemes. Pseudo- morphemes of the same kind are also encountered in words like rusty-fusty.

Those pseudo-morphemes that are attested in only one single word of a language (e.g. the morpheme cran- which can only occur in combination with one free morpheme: the morphemeberry) are termed unique morphemes or cranberry morphs. Synchronically, the semantic meaning of the unique morpheme cran- can no longer be deciphered. It cannot stand independently and even in a dictionary you will not find a lexical entry under the notion cran-.