Cottage-Style: A Double Hung window with a bottom sash that is taller in height than the top sash.
This style is commonly seen in Craftsman style houses (1900 to 1930) in the configuration shown on the left, where the six lite upper sash is paired with a unobstructed larger lower sash.
A bit about the Craftsman Style:
In A Field Guide to American Houses, Virginia and Lee McAlester explain,
The Craftsman Style was the dominant style for smaller houses built throughout the country during the period from about 1905 until the early 1920s. It originated in southern California and most landmark examples are concentrated there. Like vernacular examples of the contemporaneous Prairie style, it quickly spread throughout the country through pattern books and popular magazines. The style rapidly faded from favor after the mid-1920s; few were built after 1930. Craftsman houses were inspired primarily by the work of two California brothers – Charles Sumner Greene and Henry Mather Greene – who practiced together in Pasadena from 1893 to 1914.From about 1903 they began to design simple Craftsman-type bungalows; by 1909 they had designed and executed several exceptional landmark examples that have been called the “ultimate bungalows.” Several influences – the English Arts and Crafts movement, an interest in oriental wooden architecture, and their early training in the manual arts – appear to have led the Greenes to design and build these intricately detailed buildings. These and similar residences were given extensive publicity in such magazines as the Western Architect, The Architect, House Beautiful, Good Housekeeping, Architectural Record, CountryLife in America, and Ladies’ Home Journal, thus familiarizing the rest of the nation with the style.As a result, a flood of pattern books appeared, offering plans for Craftsman bungalows; some even offered completely pre-cut packages of lumber and detailing to be assembled by local labor. Through these pre-cut examples, the one-story Craftsman house quickly became the most popular and fashionable smaller house in the country.