Erg (landform) when liquid methane rained and eroded the ice bedrock, possibly in the form of flash floods. Alternatively, the sand could also have come from organic solids produced by photochemical reactions in Titan's atmosphere. Erg (landform) An erg (also sand sea or dune sea, or sand sheet if it lacks dunes) is a broad, flat area of desert covered with wind-swept sand with little or no vegetative cover. The term takes its name from the Arabic word "ʿarq" (), meaning "dune field". Strictly speaking, an erg is defined as a desert area that contains more than of aeolian or wind-blown sand
Arabic nouns and adjectives to ones ending in , with the masculine and feminine ' being used as adjectival forms of the concept-noun (e.g. ) depending on agreement. Thus the feminine ' of ' "partnership, cooperation, participation (definite)", ' is the Arabic word for "socialism," and the word "socialist" (both as an adjective and as the term for one who believes in socialism) is ' in the masculine and "" in the feminine. The Arabic has given rise to English adjectives of nationality for Arabic countries: Iraq"i" (from ), Kuwait"i" (from ), etc. Every verb has associated active and passive participles, as well as