The crossword solution for the term 'ON A SURFACE CONDENSE' is ADSORB, which is a 6-letter word. Adsorb is a process in which molecules of a gas or liquid are attracted and held to the surface of a solid or liquid. This process is used in many industries, such as water purification, air filtration, and chemical production. Condensation occurs when a gas is cooled and changes into a liquid, and adsorption is the process of a gas or liquid being attracted and held to the surface of a solid or liquid.