Deutsch: Hörfunk / Español: Radiocomunicación / Português: Rádio (comunicação) / Français: Radiodiffusion / Italiano: Emittente radiofonica

Radio is the wireless transmission of signals through free space by electromagnetic radiation of a frequency significantly below that of visible light, in the radio frequency range, from about 30 kHz to 300 GHz. These waves are called radio waves. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.

Deutsch: Forschung / Español: Investigación / Português: Pesquisa / Français: Recherche scientifique / Italiano: Ricerca scientifica
Research and experimental development (R&D) comprise creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of knowledge to devise new applications.

Deutsch: Einzelhandel / Español: Minorista / Português: Varejo / Français: Commerce de dêtail / Italiano: Vendita al dettaglio

Retail is the sale of goods and services from individuals or businesses to the end-user. Retailers are part of an integrated system called the supply chain. A retailer purchases goods or products in large quantities from manufacturers directly or through a wholesale, and then sells smaller quantities to the consumer for a profit.

Roofing mortar - A mortar round is a projectile which is fired with a very high trajectory and drops almost vertically onto its target before exploding.

Roof collapse when the roof of a building collapsed that resulted to lost of lives. The example of the roof collapse happened on 28 January 2006, when the roof of Katowice International Trade Hall (Miedzynarodowe Targi Katowickie) in Poland collapsed.

A Roof construction manual refers to a written set of instructions, guide, or handbook for the fabrication, building , assembly or putting together the parts of the protective covering that covers or forms the top of a building.

Roofing refers to material used to construct a building component enclosing a building above, thus providing a weatherproof shelter.

Reagent refers to a chemical species that undergoes change as a result of a chemical reaction.