The article is focused on the spelling of the combinations <-o, -e adverb + adjective>, i.e whether it should be solid or separate. A complex of problems associated with the functioning of these combinations in real writing and their standardization by rules and dictionaries is analyzed in historic and synchronic aspects. The data of the old Russian, of the XVIIIth c. are compared with modern writing. Some criteria to define the correct spelling (from historic and synchronic point of view) are suggested. Different ways of representing the combinations by rules and dictionaries were analyzed. The result of the research is a new type of spelling dictionary entries.