Lexis meaning ‘word, phrase’ (hence lexicos ‘having to do with words’) and logos

A derivational row (set) – is a group of words built according to the same pattern, the same affix.
Row unites the words with the same pattern and affixes.
head ward – направленный к голове
side ward – направленный вбок
back less ful ward – направленный назад
hand
face
arm
foot
N > V - conversion
Bn + suf >A (lacking in sth =less)


A derivational cluster – is a complex unity of ws with the same root morpheme, they are united by the root, they are close in meaning, but are built after a number of patterns, which are different. The depth of the cluster shows us the number of steps, the degree of derivation.
The volume of the cluster – is the number of derivatives in a cluster.

brotherly

↑adv
brother
to brother v← ↓n → adj brotherlike
brothership brotherless
stepbrother ↓ n
↓ brother –in-law brotherlessness (2 degree)
brotherhood

to brother-in-law (2 degree)

This method was introduced by Soboleva,
Lexical groups composed of words with semantically and phonemically identical root-morphemes are usually defined as word-families or word-clusters. The term itself implies close links between the members of the group. Such are word-families of the type: lead, leader, leadership; dark, darken, darkness; form, formal, formality and others. It should be noted that members of a word-family as a rule belong to different parts of speech and are joined together only by the identity of root-morphemes.


A derivational category – patterns of different kinds can have the same meaning that makes a derivational category.
agent
1. actress
duchess female
lioness
2. activist
capitalist
humanist
collectivity
1. hood
brotherhood
neighborhood
2. dom
kingdom
princedom
earldom
8) The functional aspect of word-building system. Productivity and activity. The main means of word-building in English.

Some of the ways of forming words in present-day English can be resorted to for the creation of new words whenever the occasion demands — these are called prоduсtive ways of forming words, other ways of forming words cannot now produce new words, and these are commonly termed non-productive or unproductive.

For instance, affixation has been a productive way of forming words ever since the Old English period; on the other hand, sound-interchange must have been at one time a word-building means but in Modern English, as has been mentioned above, its function is actually only to distinguish between different classes and forms of words.
It follows that productivity of word-building ways, individual derivational patterns and derivational affixes is understood as their ability of making new words which all who speak English find no difficulty in understanding, in particular their ability to create what are called occasional words or nonce-wоrds.
The term suggests that a speaker coins such words when he needs them; if on another occasion the same word is needed again, he coins it afresh. Nonce-words are built from familiar language material after familiar patterns. Needless to say dictionaries do not as a rule record occasional words.
Ex. (his) collarless (appearance), a lungful (of smoke), a Dickensish (office), to unlearn (the rules)
Some linguists hold the view that productive ways and means of word-formation are only those that can be used for the formation of an unlimited number of new words in the modern language, i.e. such means that “know no bounds" and easily form occasional words.
All derivational patterns experience both structural and semantic constraints. The fewer are the constraints the higher is the degree of productivity, the greater is the number of new words built on it. The two general constraints imposed on all derivational patterns are — the part of speech in which the pattern functions and the meaning attached to it which conveys the regular semantic correlation between the two classes of words. It follows that each part of speech is characterised by a set of productive derivational patterns peculiar to it.
Three degrees of productivity are distinguished for derivational patterns and individual derivational affixes:
l) highly-productive (affix ful, conversion, abbreviation)
2) productive or semi-productive (artificial creations,aff:ic,ian)
3) non-productive (interchange, aff: dom, hood).
Another approach - a quantitative approach
A derivational pattern or a derivational affix are qualified as productive provided there are in the word-stock dozens and hundreds of derived words built on the pattern or with the help of the suffix in question.