The author introduces the term RE-activities as an aggregative denomination for all activities aimed at amendment and improvement of the biological and ecological values of ecosystems and natural environment. Restoration includes not only increasing the biodiversity, but also enhancement of the original abiotic conditions (e.g. recreation of river meanders), while reclamation has more modest objectives. However even the restoration, as the most fundamental RE-activity, must be dynamical and adaptive, which means that the restored ecosystem may not be identical with the primary one, due to natural changes in the environment (succession, slightly changed climatic conditions etc.) There are no sharp boundaries between different types of RE-activity, although it can be said that nature conservation should aim at restoration of damaged or altered ecosystems, and for the sake of good environmental quality in a landscape, less thorough-going RE-activities may do. Differences in understanding due terminology in Slovak, English and German languages are discussed.