Lack of the system solution of a practical problem - a formulation of explanations for children who do not possess the general concepts became the basis for a research. Genus–differentia definitions used in this case are not suitable for an explanation as the child does not understand the general (generic) concept which is contained in a definition. To explain a generic term it is necessary to use Genus–differentia definition again that leads to formation of a chain of the general concepts which need to be explained to the child to clear the maintenance of some concept. As a result, an explanation becomes very bulky, therefore it cannot be used in case of creation of explanations for children of preschool age who, as we know, do not perceive Genus–differentia definitions.
The following arguments became the basis for formation of recommendations about a formulation of effective explanations for children of preschool age. There are two ways of a correct defining of concepts: disclosure of maintenance of a concept and disclosure of its extension. It is possible to disclose content in two ways: 1) by means of Genus–differentia definition (the generic term in the curtailed look contains information on all specific signs of an object except a specific sign), 2) through the full list of all specific signs of an object. The first of these two ways of disclosure of contents is inaccessible to children of preschool age as they do not possess generic terms, and the second - too bulky and, consequently, it is also inaccessible. The disclosure of extension of a concept is also too bulky as generally the extension of concepts contains a large number of elements. So, it is necessary to give up a thought of the formulation of explanations of word meanings for children by means of correct definitions. In that case, it is desirable to create technology of a defining which will be minimum incorrect, that is, which will promote minimization of a rejection of the contents of concepts at their assimilation by the child.
As a result of the research such a technology of formation of explanations (definitions) for children of preschool age has been substantiated. If it is impossible to call a generic term which performs, in addition, function of a categorization, it is necessary to begin a definition with a pronoun (who, that) as the generalized name of the carrier of signs. If it is impossible to report about all signs (or by means of a generic term and a specific sign, or by means of the full list of signs), it is necessary to be limited to several signs. If it is impossible to give all elements of extension, it is necessary to bring a few ones - the most widespread ones. Let's say, the definition of a bird could be such as the following: the bird is a creature who has wings, feathers, mainly flies, for example a pigeon, magpie, a rook, a titmouse. The dictionary for children of the preschool age has to contain two parts: introduction of the general concepts by means of the technology described earlier, and in the second part it is possible to use these concepts as the general concepts in Genus–differentia definitions.