Mid 16th century: from Turkish ağa 'master, lord', from Mongolian aqa.

• saga from early 18th century:

  The original medieval sagas told traditional stories of the families of Iceland and the kings of Norway. No one in Britain paid much attention to them until the 18th century, at the same time as the word saga entered the language. Its old Icelandic original is the equivalent of English saw in old saw, an old proverb or maxim, and meant ‘a narrative, a story’. From the mid 19th century saga came also to apply to stories of heroic achievement and then to novels tracing families through several generations. The 1990s gave us the Aga saga, a novel by a writer such as Joanna Trollope set in a rural location and concerning the emotional lives of characters who set great store by their Aga, a stove invented in Sweden. Aga (mid 20th century) gets its name from the initial letters of Svenska Aktienbolaget Gasackumulator, Swedish Gas Accumulator Company, the original manufacturers.

1930s: from the Swedish name (Svenskaa) A(ktiebolaget) Ga(sackumulator) 'Swedish Gas Accumulator Company', the original manufacturer.